DE3616150A1 - Electrode for corona treatment of film - consists of individual segments hinged at one end and held under pressure to yield to variations in film - Google Patents

Abstract

An electrode for corona treatment equipment etc. consists of a number of movable segments arranged singly or in groups and held under spring pressure. Each segment is held in position by a spring which allows some deflection from the operating position, all segments being locked when in the non-functional position. ADVANTAGE - The design handles plastic films without risk that they will be torn or otherwise damaged or need further treatment.

Description

The invention relates to an electrode for Corona pretreatment devices or the like with the Features in the preamble of the main claim.

With corona pretreatment devices Plastic body, especially foils Subjected to surface pretreatment in which a Arc between the charged electrode and one the insulating body carrying the plastic body, for example an insulating roller or the like, is ignited. The arc changes that Surface structure of the plastic body, the result for printing or other treatments becomes receptive.

Especially with the corona pretreatment of Plastic films there is the problem that in the Foil material defects in the form of Thickenings are included. If these thickenings in Contact with the electrode spaced from the foil come, this leads to the tear of the thin film. this has as a result that the corona pretreatment machine stopped, the damaged film part removed and the remaining film must be reinserted. In certain circumstances even a possibly upstream Foil blowing machine or the like also to be stopped.

From DE-OS 34 30 210 it is known an electrode to divide into individual segments, which in themselves from a Rest position in a working position can. In the working position, these segments are each  held by a clamping spring. These segments can with a correspondingly smooth setting Dodge thickening in the film, taking it out of the The spring gets jammed. The segments then take but undefined intermediate positions in which you Distance from the film has become so large that none Arc can be ignited at this point. The The film remains in the area of the pivoted and stopped segments untreated. However, are the segments set relatively stiff, it can also come to tear the film.

It is therefore an object of the present invention to Possibility to pretreat faulty foils to show when the film is cracked or a subsequent treatment failure can be avoided.

The invention solves this problem with the features in Characteristic of the main claim.

According to the invention, the actuating spring has not only one Clamp function in the working position, it is loaded rather the segments over the entire delivery route. At an electrode consisting of several segments the springs on each individual segment or on a group of segments, depending on the desired Fine division, attack. The invention Spring allows the segment to thicken in dodge the film and then immediately again to get into the working position. With certain Segment shapes with several spray tongues can be used here even the film itself in the area of thickening be pretreated. When moving back the segment in the working position and after that is done again anyway a normal pre-treatment.  

After the segments under constant spring loading stand, it is recommended that one of the To provide spring force counteracting locking. This can on the one hand in a separate locking device, for example, a clamping device.

In a preferred embodiment of the invention is, however, the single spring as a dead center spring trained who after passing the dead center presses the assigned segment into the rest position and there holds on. This is additional locking devices dispensable.

The actuating spring according to the invention can vary be designed, for example as a spiral spring, Tension spring, compression spring or the like. Especially however, it is advantageous to use a leaf spring, with a dead center spring can be formed and the other on special inexpensive and simple way using as a spring band punched tongues for a row of segments can be produced is.

The spring according to the invention can for all types of movable segments are used. In the Subclaims are further advantageous Embodiments for pivoting and sliding stored segments specified.

The invention is in the drawings for example and shown schematically. In detail show:

Fig. 1 a pivotable segment with a spring in working, and dead center position of rest,

Fig. 2 shows a slidably mounted segment with an actuating spring in the working, dead center and rest position

FIGS. 3 and 4 in a pivotally mounted segment variation to Fig. 1 in different positions.

Fig. 1 shows an electrode ( 1 ) in cross section, which is formed from a series of segments ( 2 ) arranged one behind the other. The segments ( 2 ) are in electrical connection with a generator (not shown), as a result of which an arc is ignited between an externally insulated and grounded roller ( 3 ) and a film ( 12 ) located thereon. Fig. 1 shows, in solid lines, the individually pivotable and deliverable segments ( 2 ) in the working position near the roller ( 3 ) at a stop ( 6 ). In the rest position shown in dashed lines, the segments ( 2 ) are folded against the roller ( 3 ) against a stop ( 5 ). Fig. 1 also shows the dead center position, also shown in dashed lines.

The segments ( 2 ) each have on their rear side a groove ( 10 ) which runs along the pivot axis and in which an adjusting spring ( 7 ) engages for each segment. The adjusting springs ( 7 ) are each designed as leaf springs which are movable in the bent position on one side in the groove ( 10 ) and firmly clamped on the frame ( 11 ) on the other side.

The spring design and its point of application are chosen so that the actuating spring ( 7 ) functions as a dead center spring. In the working position, the segment ( 2 ) is held by the adjusting spring ( 7 ) at the stop ( 6 ). The segment ( 2 ) can deflect thickened portions ( 4 ) in the film ( 12 ) against the spring force upon contact and is moved back into the working position behind the thickened portion. Only when the segment ( 2 ) exceeds the dead center position is it moved by the actuating spring ( 7 ) against the stop ( 5 ) in the rest position and held there. In order to give the segment ( 2 ) the largest possible escape path, the design and arrangement of the adjusting spring ( 7 ) and groove ( 10 ) is such that the dead center position is only reached shortly before the segment abuts the stop ( 5 ).

Fig. 2 shows a variation of the first embodiment, a segment ( 2 ) which is mounted in the frame ( 11 ) slidably via an elongated hole guide. The adjusting spring ( 7 ) is designed as a curved leaf spring which is firmly clamped on the frame ( 11 ) and engages in a groove ( 10 ) on the segment ( 2 ). The actuating spring ( 7 ) is also designed as a dead center spring and is guided between two stationary cover pins ( 8 ) for this purpose.

In the working position, shown with solid lines, the segment ( 2 ) is pulled against the frame ( 11 ) by the actuating spring ( 7 ) located between the cover pins ( 8 ) with a stop, not shown. Here, the spring-loaded segment ( 2 ) can thicken ( 4 ) a large part of the feed path. When exceeding the dead point in which the spring (7) against the right envelope pin (8), is bent from this envelope pin (8), the spring (7) to the other side and the segment (2) in the rest position against a stop, not shown pressed. When it is re-positioned, the spring ( 7 ) is then bent again in the opposite direction by the left-hand envelope pin ( 8 ).

FIGS. 3 and 4 show variation to Fig. 1 also a pivotally mounted segment (2) having on its underside a cam (9), the spring (7) in the form of a pre-bent leaf spring applies flat against the. Fig. 3 shows the bold working position and the dead center position shown in dashed lines. 4 shows only the rest position.

The shape and arrangement of the cam ( 9 ) and the actuating spring ( 7 ) in relation to the pivot axis of the segment ( 2 ) are in turn such that there is a dead center position which is reached shortly before the rest position of the segment ( 2 ) at the stop ( 5 ) becomes.

In the exemplary embodiments shown, the electrode ( 1 ) consists of a number of segments ( 2 ) arranged next to one another. The electrode ( 1 ) is thus also assigned a series of adjusting springs ( 7 ) arranged next to one another. The row of actuating springs ( 7 ) can thus be designed as a comb-shaped spring band, the individual actuating springs ( 7 ) being formed by punched-out tongues. The individual segments ( 2 ) with their springs ( 7 ) can thus be moved into the working position or moved back to the rest position independently of their neighbors.

• Parts list: 1 electrode
  2 segment
  3 roller
  4 thickening
  5 stop
  6 stop
  7 spring
  8 envelope pen
  9 cams
  10 groove
  11 frames
  12 slide

Claims (8)

1. Electrode for corona pretreatment devices or the like, consisting of several movably mounted and individually or in groups deliverable segments, which are locked spring-loaded in the working position, characterized in that each of the segments ( 2 ) engages an adjusting spring ( 7 ) which the segments ( 2 ) in the working position and a resilient evasion of the segments ( 2 ) allows from the working position, and that the segments ( 2 ) are held in the rest position by a locking device. 2. Electrode according to claim 1, characterized in that the adjusting spring ( 7 ) is designed as a dead center spring which also locks the segments ( 2 ) in the rest position. 3. Electrode according to claim 1 or 2, characterized in that the actuating spring ( 7 ) is designed as a leaf spring. 4. Electrode according to claim 3, characterized in that the actuating spring ( 7 ) on the segment ( 2 ) in a groove ( 10 ) or the like is attached. 5. Electrode according to claim 3, characterized in that the segments ( 2 ) have a cam ( 9 ) on which the actuating spring ( 7 ) bears. 6. Electrode according to claim 4, characterized in that the adjusting spring ( 7 ) is guided in the form of a curved leaf spring between two envelope pins ( 8 ). 7. Electrode according to claim 2 or one of the following, characterized in that the dead center position of the adjusting spring ( 7 ) is only shortly before the rest position of the segment ( 2 ). 8. Electrode according to claim 1 or one of the following, characterized in that the row of actuating springs ( 7 ) is designed as a spring band with punched tongues.