DE1094583B - Method and device for rapid switching of cinematographic films - Google Patents

Description

GERMAN

The invention relates to a method and a device for fast switching kinematographi shear films according to patent application F 20794 IX / 57 a, in which the film is fed from the supply drum to the picture window via a film loop. and pneumatic acceleration forces in interaction with mechanical clamping devices create a curved film path for the films rapidly moving through the image window, as a result of which the film movement is ended and the position of the film in the image window is determined.

Numerous constructions have already become known for the rapid advancement of cinematographic films. With these difficulties arise because either the achievable switching time for some applications, especially for the recording of television programs according to the in Central European standard, is too long or because the stress on the film material is inadmissible is high. The latter increases the risk of film tears and thus of disruptive business interruptions. In addition, when the film material is subjected to high loads, it is stretched considerably and kicked Expansions in the film strip, which are locally different and what causes this during the presentation Film's image stability is impaired.

The invention aims to develop the teachings of patent application F 20794 IX / 57 a relatively little technical effort with fast, jerky advancement of the film to improve the image status achieved so far with such arrangements.

According to the invention it is provided for this that a side edge of the film in the area of the picture window against a contact surface at at least three locations separated by at least two image heights and the film is adjusted to the side in the image window.

It is useful here to design the film guide in the area of the picture window in such a way that at least one of the points at which the film edge is pressed against a contact surface in front of the image window (based on the direction of movement of the film) and at least one point after the image window is arranged. The film web runs in the area of the picture window S-shaped, and through the lateral three-point guide, a good lateral image position is achieved in the image window.

In a preferred embodiment, a side edge of the film can be pressed against a contact surface by a stream of air at a point immediately in front of the picture window. It is advantageous if the film is guided in an arc at this point and in each case according to the area of the image method and device
for quick switching
cinematographic films

Addition to patent application F 20794IX / 57 a
(Auslegeschrift 1 073 859)

Applicant:

TV G.m.b.H.,

Darmstadt, Am Alten Bahnhof 6

Dr. Rolf Möller, Darmstadt-Eberstadt,
has been named as the inventor

window taking place release as a result of the then beginning transport movement of the film of the sheet is shortened until finally the curved piece of film rests against a convex film guide and thereby the film transport is limited and there the contact surface is at least one, preferably has multiple channels through which the air compresses underneath the shortening film can escape faster in the area of the guided film edge than in the area of the other edge of the film, so that the resulting pressure gradient is the guided side edge of the Film presses against the contact surface.

In the following, the invention is described in connection with an exemplary embodiment of the subject matter of the invention descriptive figures. These are purely schematic representations in which everything for Understanding of the invention is not absolutely necessary is omitted for the sake of clarity. Corresponding details are in all Figures included in the same way. It shows

Prop. 1 the film transport device of a film camera for recording television programs;

2 shows the resilient lateral film guide in the area of the gripper,

3 shows a longitudinal section through the antechamber above the picture window,

4 shows a cross section through the antechamber.

In the arrangement shown in Fig. 1, the runs from a (not shown) film supply drum running film 1 over a toothed drum 2 rotating at continuous speed and is

009 677/174

A gripper 5 inevitably so via a film channel formed from the two guide rails 3 and 4 supplied that the teeth of this gripper always correctly engage in the holes of the film perforation. Through this the introduction of the films is made much easier. The full or dashed line in two positions The drawn gripper advances the film step by step. One arranged immediately behind the gripper Clamping device 6 releases the film during the advancing movement of the gripper, clamps it but stuck during the rest of the time. Since the film during the transport movement of the gripper 5 in Area of the image window 7 is clamped by a further clamping device 8, it forms above the Image window a loop 9 drawn in dashed lines. The film runs through below image window 7 arcuate (indicated in the figure by a dashed line) a pneumatic film transport chamber 10 and is made from this via a toothed drum 11 rotating at continuous speed fed to the winding drum (not shown). The inside of the pneumatic film transport chamber 10 is connected to a suction air line through an opening 12 so that inside the chamber there is a negative pressure.

As soon as the clamping device 8 releases the film in the area of the picture window, the atmospheric air pressure acting on the inside of the sheet of film pushes the film into the interior of the pneumatic film transport chamber; as a result, it is quickly moved past the picture window, and in the process the loop 9 located above the picture window, shown in broken lines, is shortened until the film finally rests firmly against the convex film guide 13 there. The film now has the position shown in FIG. 1 by a solid line. The film is then clamped again in the area of the picture window by the clamping device 8, and the toothed drum 11 gradually transports the film out of the pneumatic film transport chamber 10, so that the film sheet there shortens and finally assumes the position shown in dashed lines again. At the same time, the clamping device is opened again, and the gripper 5 transports the film by one film frame height, so that it again assumes the position shown in dashed lines above the picture window.

From FIG. 2 it can be seen how the film 1 is pressed against the contact surface 15 in the region of the gripper 5 will. For this purpose, the runner 20 is pressed against one edge of the film by means of the spring 21 and in this way it is ensured that the other edge of the film is continuously in contact with the contact surface 15.

The second point at which the film is laterally guided is in the area of the film loop 9. The film guide is designed like a chamber there, and two depressions 17 and 18 are arranged in one side wall 16 of this chamber serving to guide the film laterally. During the jerky shortening of the film loop 9 in the region of the facing longitudinal edge of the film, the depressions promote the escape of air from the bottom to the top of the film. The pressure of the air compressed under the loop will therefore be lower in the area of this edge than in the area of the other edge of the film, where greater air congestion will occur. This air stagnation causes the film to be pressed with its one longitudinal edge against the side wall in which the lateral depressions are arranged. As a result of the pressure gradient spreading beneath the film during the jerky progression from one longitudinal edge to the other longitudinal edge, the film is gently but steadily pressed against the side wall provided with depressions. In Fig. 4, the two extreme positions of the film are denoted by 1 α and 1 b.

It is not inconsistent with the invention if not just one but both side walls of the Chamber can be indented, but is

ίο in this case make sure that the drainage the air from the bottom to the top of the film in the area of one film edge is essential can be done more easily than in the area of the other Filmkaiite, so that the film through it on its The pressure gradient forming the bottom is gently pressed against the first-mentioned chamber wall.

In the pneumatic film transport chamber there is an arc-shaped delimitation piece which is adapted to the film sheet 14 arranged such that the film is pressed against it at the end of its brief rapid movement and its kinetic energy is slowed down. This avoids that the clamped at 6 Film in the area of the convex film guide 13 and in the area of the picture window 7 through the braking of the inertia forces is excessively stressed on elongation. It therefore becomes the vertical The film status in the area of the image window has been significantly improved.

This arcuate delimitation piece is arranged such that the film is only on one of its both edges, preferably on the perforated side, impacts against the delimitation piece, so that it thereby evading in this area due to elastic deformation to the other side and there with its edge touches the associated side wall of the chamber.

Since the film changes from a convex to a concave curvature in the area of the image window, so S-shaped curved, the arrangement of the contact points of the film is both in the area of the covex and laterally adjusted in the area of the concave curvature. It is believed that this Adjustment, both of the preceding convex as well as the following concave film sheet, in The area of the picture window, which lies between convex and concave film arcs, is a special one causes good film guidance practically free of lateral fluctuations.

Claims (4)

PATENT CLAIMS: 1. Method for fast switching of cinematographic films according to patent application F 20794 IX / 57 a, in which the film is transferred from the supply drum to the picture window via a film loop is supplied and pneumatic acceleration forces in interaction with mechanical Clamping devices apply the film, which is rapidly moving through the image window, to a curved film path, thereby causing the film to move ended and the position of the film in the image window is determined, characterized in that that one side edge of the film in the region of the picture window is at least three from each other pressed against a contact surface at least two image heights away and thereby the Film is aligned in the image window. 2. Device for performing the method according to claim 1, characterized by such a design of the film guide in the area of the picture window that at least one of the Places at which the film edge is pressed against a contact surface in front of the image window (related on the direction of movement of the film) and arranged at least one point after the picture window is. 3. Apparatus according to claim 2, characterized in that one side edge of the film at a location preferably immediately in front of the picture window by an air stream is pressed against a contact surface. 4. Apparatus according to claim 3, characterized in that at this point the film is arcuate is performed and in each case after the release taking place in the area of the picture window as a result of the then the beginning of the transport movement of the film, the sheet is shortened until finally the sheet- shaped piece of film rests on a convex film guide and thereby the film transport is limited, and that there the contact surface at least one, preferably several Has channels through which the air compressed below the shortening film can escape faster in the area of the guided film edge than in the area of the other Film edge, so that the resulting pressure gradient the guided side edge of the Film presses against the contact surface. Considered publications:
German patents No. 805 493, 849 215,
352; German utility model No. 1 698 569. 1 sheet of drawings