Cutting – Tool or tool with support – Cutting couple type
Patent
1992-10-02
1994-08-16
Phan, Hien H.
Cutting
Tool or tool with support
Cutting couple type
83620, 8369871, 29515, 295251, B26F 102
Patent
active
053376420
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The invention relates to a punch block support arm, as well as to a process for mounting punches on such a block.
BACKGROUND ART
Parallel to their edges, photographic films, for example, incorporate one or two arrays of perforations which enable the film to be driven in devices for, exposing images onto and projecting images from the film, and in processing machines. In the use of photographic films, it is known that the quality of the projection, particularly the stability of the images on the screen, is closely dependent on the quality of the perforations, i.e. on the constancy of their pitch and on the accuracy of execution of each perforation. In this respect, the tolerance required is extremely fine, in the order of only a few microns on the finished perforation.
The accuracy of execution of the perforations depends on the accuracy of the movement of the punches at the time of perforation, though it also depends on the accuracy of mounting said punches.
In reciprocating movement type perforators, the punches are generally mounted on a block of a suitable thickness. The block is fastened to the upper jaw of the perforating device, and it is arranged so that the punches cooperate periodically with a die block held on the lower jaw of the perforating device.
FIG. 1 represents a punch block support am on which the punches are mounted as in the earlier technique. The block represented comprises an array composed of 15 punches 1. The arrangement of these punches is represented in greater detail in FIG. 2. Each punch is housed in a recess 2 of suitable size and shape to receive on the one hand the punch 3 and on the other hand a positioning wedge 4 arranged so as to press on two adjacent faces of punch 3.
Wedge 4 is arranged so that its axis 5 forms an angle of approximately 45.degree. in relation to the alignment axis 6 of the punches. Recess 2 is extended along axis 5 so as to receive a screw 7 intended to press on wedge 4, thereby immobilising punch 3 at the same time along alignment axis b of said punches and along an axis perpendicular to the alignment axis. According to this technique, the positioning of the punches is adjusted individually. The drawbacks of such a technique are mainly as follows : punch is no longer held in position; associated with two adjacent punches being relatively close to each other and this can prevent the use of screws of sufficient size to achieve the required tightening; positioning wedges is relatively complex to achieve and involves fairly long construction times.
SUMMARY OF THE INVENTION
Therefore, one of the objects of this invention is to realise a punch block support arm, as well as a process for mounting punches on such a punch block support arm, which are simpler and cheaper than those of the earlier technique.
Another object of this invention is to permit more reliable positioning of the punches on a punch block support arm.
Other objects of this invention will appear during the more detailed description which follows.
The objects of this invention are achieved by providing a punch block support arm comprising at least one array of at least two punches, characterised in that to the alignment axis of said punches, as well as in their own longitudinal direction, is realised by means of a screw associated with each of the punches of the array; and alignment axis of the punches is achieved by means of a narrow slot across the whole block thickness, the slot extending along the entire length of the punches. The slot extends, at each of its ends, perpendicular to the alignment axis of the punches, in order to define a longitudinal bar and two portions of transversal bars, the slot being located so that the distortion of the longitudinal bar brings relatively closer the portions of transversal bars so as to immobilise the punches.
According to this invention, a process is also realised for mounting punches on a block, the punches being arranged in arrays comprising at least two punches in which : to the alignment axis of the punches, as well as in t
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Eastman Kodak Company
Phan Hien H.
Snee, III Charles E.
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