Cutting – Cutting motion of tool has component in direction of moving... – Tool carrier shuttles rectilinearly parallel to direction of...
Patent
1992-09-17
1993-11-23
Terrell, William E.
Cutting
Cutting motion of tool has component in direction of moving...
Tool carrier shuttles rectilinearly parallel to direction of...
493369, B26D 158, B26D 160
Patent
active
052633934
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a device for carrying out an operation, according to a given pitch, on a uniformly and continuously movable web; it relates in particular to the perforation of photographic films, and to the cutting, embossing, stitching and notching of web products.
Photographic films, for example, incorporate, parallel to their edges, one or two arrays of perforations making it possible to drive a film in devices for shooting and for projection, and in processing machines. It is known that, in the use of photographic film, the quality of projection, particularly the stability of the image on the screen, is closely dependent on the quality of the perforations, i.e. the regularity of their pitch and the accurate execution of each perforation. In this respect, the tolerance levels required are extremely low, in the order of only a few microns on the finished perforation.
To this end, perforators are usually employed which cut a perforation at the same time on one or both of its edges each time that the film is immobilised between two successive movements of the film in the perforator. The film is driven intermittently in a perforation station by a reciprocating mechanism using a claw which engages in a perforation made previously by an alternative punch which perforates the film. In order to obtain a precisely reproducible pitch, a cooperating pin is used which moves with the punch. This pin is usually situated between the punch and the claw, at a distance from the punch equal to the pitch of the perforations. This is arranged so that the pin penetrates inside the perforation which was cut previously before the punch comes into contact with the film; the purpose of this is to position the film with great precision under the punch before the perforation is made. This pin, which enters without play into the perforation, corrects small errors in positioning of the film due to the claw.
Thus, patent FR 2 093 796 describes a perforator for punching perforations on a web according to a regular pitch; it comprises a punch block support arm joined along a horizontal axis on a die block support arm, and it also consists of a feed mechanism for driving the web step by step, said mechanism being composed of a claw driven by an arm mounted on an offset part, a perforation station for cutting the perforations, and a reception mechanism which cooperates with the accurately perforated web, in order to accurately position the web to be perforated in the reception station. Particularly on account of the arrangement of the punch and die block support arms in relation to the direction of movement of the web, such a device can only realise one hole at a time on each side of the web. For this reason, the perforator described in the patent referred to above allows a rate which cannot exceed 30 to 40 m/min.
According to another known device, webs are perforated in a continuous manner by means of a rotating system. Thus, patent FR 2 315 367 describes a device comprising a punch support drum driven by a continuous rotation movement around its axis and incorporating, built onto its rim, at least one punch, which is stationary in relation to said drum, and also comprising a web transport support, of the endless type (preferably a drum with an axis parallel to that of the punch support drum), arranged close to the rim of said punch support drum and driven by a continuous movement synchronous with that of the latter, said endless support, on which the web to be perforated is positioned, incorporating at least one die block suitable to cooperate with said punch at the time of the joint movements of said drum and said support. Such devices can operate at very high speeds, but for this purpose they require very high precision mechanisms and, therefore, they are very costly.
Consequently, one of the objects of this invention is to supply a device for carrying out an operation according to a given pitch on a web movable continuously at speeds of up to 100 m/min.
Another object of this invention is to supply a device which can be mod
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Gaudillat Jacques E.
Long Michael
Eastman Kodak Company
Snee, III Charles E.
Terrell William E.
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