Apparatus for cleaning surfaces

Abstract

An apparatus for cleaning surfaces of a printing press has an adjusting device having a pressing element for pressing a cleaning element against the surface to be cleaned when needed. The adjusting device has a drive for moving the pressing element relative to the surface to be cleaned between a home position, in which the cleaning element is positioned at a distance from the surface to be cleaned, and a cleaning position in which the cleaning element is in contact with the surface to be cleaned or, respectively, is in the direct proximity of the surface to be cleaned. An overload safety device is configured to respond upon a critical force acting on at least one of the adjusting device or pressing element being exceeded and to move the pressing element into an overload position.

Claims

1. An apparatus (1) for cleaning a surface of a printing press, the apparatus (1) comprising: an adjusting device having a pressing element (5) configured to press a cleaning element against the surface (100) to be cleaned, the adjusting device being configured to move the pressing element (5) in linear motion relative to the surface (100) to be cleaned between a home position, in which the cleaning element is positioned at a distance from the surface (100) to be cleaned, and a cleaning position in which the cleaning element is in contact with the surface (100) to be cleaned; and an overload safety device (10) being configured to sense when a force applied to at least one of the adjusting device and the pressing element (5) exceeds a defined force limit, and in response thereto, move the pressing element (5) to an overload position; wherein the overload safety device (10) is configured to move the pressing element (5) into the overload position in one of a linear motion, a circular motion, and a superposition of linear and circular motion upon the activation of the overload safety device (10).

2. The apparatus according to claim 1, wherein the overload position differs from the home position and the cleaning position.

3. The apparatus according to claim 1, wherein the overload position corresponds to a position of the pressing element (5) in which the pressing element (5) is not in contact with the surface (100) to be cleaned.

4. The apparatus according to claim 1, wherein the overload safety device (10) is configured to keep the pressing element (5) in the overload position after the first force applied on the one of the adjusting device and the pressing element (5) exceeds the defined force limit.

5. The apparatus according to claim 1, wherein the overload safety device (10) is configured to move the pressing element (5) back into the cleaning position as soon as the first force applied on the one of the adjusting device and the pressing element (5) falls below a second defined force limit.

6. The apparatus according to claim 1, wherein the overload safety device (10) is regenerative.

7. The apparatus according to claim 6, wherein the overload safety device (10) comprises a mechanism (11) configured to respond upon the exceeding of the defined force limit and move the pressing element (5) into the overload position pursuant to a predefined sequence of events.

8. The apparatus according to claim 7, wherein the mechanism (11) comprises a guide which is designed to convey the pressing element (5) into the overload position in a guided motion upon activation of the overload safety device (10).

9. The apparatus according to claim 6, wherein the overload safety device (10) comprises a spring-loaded lever mechanism (12) configured to respond upon exceeding the defined force limit and move the pressing element (5) into the overload position.

10. The apparatus according to claim 1, wherein the adjusting device together with the pressing element (5) is mechanically connected to a base element of the cleaning apparatus (1).

11. The apparatus according to claim 10, wherein the base element is configured to move relative to and along the surface (100) to be cleaned.

12. The apparatus according to claim 10, wherein the overload safety device (10) comprises at least one frangible element (13) which upon the exceeding of the defined first force limit, mechanically disconnects the at least one of the adjusting device and the pressing element (5) from the base element of the cleaning apparatus (1) such that the at least one of the adjusting device and pressing element (5) respectively is moved away from the surface (100) to be cleaned.

13. The apparatus according to claim 1, wherein a sensor device (14) is configured to detect whether the pressing element is in the overload position and emit a corresponding warning signal.

14. The apparatus according to claim 1, wherein the adjusting device comprises a variably adjustable feed limitation for the selective defining of a maximum displacement path of the pressing element (5) able to be realized by the drive relative to the surface (100) to be cleaned.

15. The apparatus according to claim 14, wherein the feed limitation (10) comprises a stop (15) having a strike surface for limiting the maximum displacement path of the pressing element (5) able to be realized by the drive relative to the surface (100) to be cleaned.

16. The apparatus according to claim 14, wherein the apparatus is configured to selectively automatically set the feed limitation as at least one of a function of the diameter of a cylinder (101) to be cleaned and a function of a contact pressure.

17. The apparatus according to claim 1, wherein the cleaning element (8) comprises a cleaning cloth, and wherein the apparatus (1) further comprises a clean cloth take-up roller (6) for supplying unused cleaning cloth; and a dirty cloth take-up roller (7) for receiving used cleaning cloth; and wherein the pressing element (5) is designed to press the cleaning cloth provided by the clean cloth take-up roller (6) against the surface (100) to be cleaned as needed.

Description

DESCRIPTION OF DRAWINGS

(1) FIG. 1 a schematic side view of an example embodiment of the cleaning apparatus according to the invention which is realized as a wash bar for cleaning and/or washing the surface area of a printing press cylinder, wherein the pressing element of the cleaning apparatus is in its home position; and

(2) FIG. 2 a schematic side view of the example embodiment of the inventive cleaning apparatus according to FIG. 1 in a state in which the adjusting device is in the overload position.

DETAILED DESCRIPTION

(3) The accompanying drawings will be referenced below in describing an example embodiment of the inventive cleaning apparatus 1.

(4) The example embodiment depicted in the drawings relates specifically to an apparatus 1 for cleaning the surface areas 100 of a printing press cylinder 101 configured as a wash bar. The cleaning apparatus 1 is in particular suitable for cleaning blanket cylinders of offset printing presses, thus cylinders 101 covered by a rubber blanket which serve to transfer the print image to the actual impression cylinder.

(5) During printing, little by little, impurities, essentially printing ink and dust, get left behind on the rubber blanket. These contaminants need to be periodically removed if a qualitatively flawless print image is to be produced. Cleaning the rubber blanket from time to time is therefore a common practice.

(6) To that end, the example embodiment of the inventive cleaning apparatus 1 depicted schematically in the drawings can be used.

(7) The invention is not, however, limited to the cleaning of blanket cylinders which transfer a print image. In fact, the inventive cleaning apparatus 1 is also suited to cleaning flexo, steel or chrome cylinders. Use with cast cylinders or calendars respectively of film extrusion machines is also conceivable. Accordingly, the inventive apparatus can not only remove dust (paper dust) and ink from the surface of the object to be cleaned but also film particles, extrusion particles, etc.

(8) The printing press cylinder 101, which can be washed/cleaned by the cleaning apparatus 1 depicted in the drawings and configured as a wash bar, can however also be a different cylinder or any other cylinder of an offset printing press or other printing press.

(9) To clean the surface area 100 of the printing press cylinder 101, the cleaning apparatus 1 depicted as an example in FIG. 1 comprises a cleaning element 8 in the form of a cleaning cloth.

(10) As indicated schematically in FIG. 1, the example embodiment of the inventive cleaning apparatus 1 is arranged opposite from the cylinder 101 of a printing mechanism of a printing press, for example opposite a web-print rubber blanket cylinder of a web-fed rotary offset press, wherein the cleaning apparatus 1 is periodically activated for the purpose of cleaning the surface area 100 of the cylinder 101.

(11) The cleaning apparatus 1 comprises an adjusting device with a pressing element 5, in front of which runs the cleaning element configured as a cleaning cloth opposite from the surface area 100 of the cylinder 101 to be cleaned. A conventionally designed cloth drive unwinds the cleaning element 8 configured as a cleaning cloth from a supply roll (clean cloth take-up roller 6).

(12) For the purpose of cleaning the surface area 100 of the cylinder 101, the adjusting device provided with the pressing element 5 shifts from the rest position (home position) indicated in FIG. 1 into a cleaning position, which is a position in which the cleaning element 8 designed as cleaning cloth presses against the cylinder 101. The required contacting position, or cleaning position respectively, for the contact of the cleaning cloth is effected by the action of variable contact pressure, on which the frictional force depends.

(13) Preferably, the contact pressure and/or the maximally effectable displacement path from the rest position (home position) out toward the surface 100 to be cleaned is variably adjustable, and namely by the maximally realizable path of displacement of the pressing element 5 relative to the surface 100 to be cleaned being individually specified by means of an adjustable feed limitation.

(14) Although not recognizable in FIG. 1, it is preferably provided for the adjusting device to comprise a drive, by means of which the pressing element 5 can be moved relative to the cylinder surface 100 to be cleaned. Specifically, a pneumatic drive is used as the adjusting device drive in the example embodiment of the inventive cleaning apparatus 1 depicted in the drawings.

(15) The pneumatic drive in particular comprises a pneumatic cylinder disposed between a carriage arrangement 2 and a baseplate of the cleaning apparatus 1. The carriage arrangement 2, on which the pressing element 5 is arranged, is displaceable toward the surface 100 to be cleaned relative to the baseplate upon actuation of the pneumatic cylinder.

(16) To this end, an actuating element extends from the pneumatic cylinder in the example embodiment of the inventive cleaning apparatus 1 depicted in the drawings, striking the strike surface of a stop in order to thereby define the degree to which the actuating element can be extended. The cited stop defines a feed limitation in this example embodiment, by means of which the maximum displacement of the pressing element 5 able to be realized by the drive relative to the surface 100 to be cleaned can be specified.

(17) When the pressing element 5 is extended out of its home position shown in FIG. 1 toward the surface 100 to be cleaned for the purpose of cleaning the cylinder surface 100, whereby the cleaning element configured as a cleaning cloth is pressed against the cylinder 101 to be cleaned in this cleaning position, there is the risk of larger particles such as for example defect cardboard being inadvertently transported along over the cylinder 101 into the region in which the cleaning element is being pressed against the surface 100 of the cylinder 101 by the pressing element. In such a situation, there is the danger of the cleaning apparatus 1 being damaged, and in particular the pressing element 5 of the cleaning apparatus 1.

(18) In order to therefore effectively protect the cleaning apparatus 1 from such damage, the inventive cleaning apparatus 1 comprises an overload safety device which is designed which is designed to respond upon a predefinable or defined critical force acting on the adjusting device or the pressing element 5 being exceeded and to convey the adjusting device with the pressing element 5 into an overload position.

(19) FIG. 2 shows a schematic view of the example embodiment of the inventive cleaning apparatus 1 according to FIG. 1 is in its overload position.

(20) It is evident that the overload safety device employed in the example embodiment of the inventive cleaning apparatus 1 depicted in the drawings is designed such that upon the predefinable or defined critical force acting on the adjusting device or pressing element 5 respectively being exceeded, the adjusting device and the pressing element 5 are conveyed into an overload position which is different from the home position and the cleaning position of the pressing element 5.

(21) Specifically, the overload position in the embodiment depicted in the drawings is selected so as to correspond to a position of the adjusting device, or the pressing element 5 respectively, in which the adjusting device and the pressing element 5 are removed from a flow of force transmitted from the surface 100 to be cleaned to the pressing element 5.

(22) In the embodiment of the inventive cleaning apparatus depicted schematically in the drawings, the overload safety device comprises a spring-loaded toggle lever mechanism which is designed to respond upon the critical force acting on the adjusting device or the pressing element 5 being exceeded and convey the adjusting device with the pressing element 5 into the overload position shown in FIG. 2. The adjusting device and the pressing elements 5 are thereby conveyed into the overload position according to a preset sequence of events. To this end, the adjusting device and the pressing element are conveyed by a guided motion into the overload position when the overload safety device is actuated.

(23) Although the overload safety device in the example embodiment depicted in the drawings exhibits a mechanism designed to convey the adjusting device and the pressing element into the overload position in a circular motion when the overload safety device is actuated, it is nonetheless conceivable for the adjusting device and the pressing element to be conveyed into the overload position in a linear motion or in a superposition of linear and circular motion upon activation of the overload safety device.

(24) The present invention is also not limited to an overload safety device comprising a preferably spring-loaded toggle lever mechanism to convey the adjusting device and the pressing element into the overload position upon activated overload safety device. Other mechanisms, particularly lever mechanisms, are in fact also conceivable for this conveyance.

(25) The example embodiment of the inventive cleaning apparatus depicted in the drawings is characterized by the overload safety device being of completely regenerative design.

(26) In detail, and as can be noted from the FIG. 2 depiction, the overload safety device is designed to hold the adjusting device and the pressing element 5 in the overload position after the critical force acting on the adjusting device and on the pressing element 5 has been exceeded.

(27) Furthermore, the overload safety device is preferably designed to thereafter convey the adjusting device with the pressing element 5 back into the home position or the cleaning position, wherein this requires no components of the overload safety device being replaced.

(28) Alternatively hereto, it would however also be conceivable for the overload safety device to be of at least partly destructive design and comprise at least one breakaway or shear-off element which responds upon the exceeding of the critical force acting on the adjusting device or the pressing element 5 and thereby loses its original connecting function such that the adjusting device and the pressing element are then removed from the flow of force conducted from the surface 100 to be cleaned.

(29) The invention is not limited to the example embodiment of the inventive washing apparatus 1 depicted in the drawings but rather yields from an integrated consideration of all the features disclosed herein in context.