US 3600997 A
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United States Patent Inventor Werner Schmidt Cologne-Sub, Germany Appl. No. 846,075
Filed July 30, 1969 Patented Aug. 24, 1971 Assignee Rbelnische Braunkohlenworlte AG Cologne, Germany Priority Aug. 2, 1968 Germany P 17 61 993.1
1 METHOD OF AND APPARATUS FOR EFFEC SEVERANCE OF WEBS IN RESPONSE TO CHANGE IN TRANSPARENCY ALONG THEIR TING Primary Examiner-James M. Meister Attomey-Edwin E. Greigg ABSTRACT: In order to automatically cut to size nonuniformly spaced photographs arranged serially to constitute a continuous web, a cutting mechanism to sever the web transversally is operated upon sensing the change in the transparency of the web between a dark margin that frames each photograph and a light strip separating each margin from that LENGTH of an ad acent photograph. There are provided a first a Cums 2 Drawing Figs photoelectric sensing station which generates a control signal US. Cl. 83/364, to stop the web feed and effect cutting when the leading edge 83/210, 83/365, 83/37 I 250/219 PR of a photograph coincides with the severing path of the cutting Int. Cl. 826d 5/34 mechanism and a second photoelectric sensing station which Field ofSearch 83/210, generates a control signal to stop the web feed and effect 209, 364, 365, 371; 250/219 WD,219 LG, 219 cutting when the trailing edge of the same photograph coin- TH, 219 FR cides with said severing path.
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2/ I l8 1 L METHOD OF AND APPARATUS FOR EFFECTING SEVERANCE OF WEBS IN RESPONSE TO CHANGES IN TRANSPARENCY ALONG THEIR LENGTH BACKGROUND OF THE INVENTION This invention relates to a method of and apparatus for actuating a cutting deviceto sever a strip or web of indefinite length into portions of predetermined size. The web is of the type whose transparency regularly and abruptly varies along its length. Such a feature is characteristic, for example, of a web of photographic paper which has, along its length, a series of photographs-such as transparencies or the likeof uniform size. Each such photograph is framed by a peripheral dark margin of small transparency and is separated from one another by a blank (light) strip of great transparency extending transversally of the web. The spacing of the photographs from one another is usually nonuniform and thus the light separating strips are, accordingly, of differing widths. In order to ensure that the transversal cuts correspond to the exact lateral limits of the photographs themselves, the severing operation has heretofore been performed manually. Such manual operation, however, is very time consuming and requires an excessive amount of labor.
OBJECT AND SUMMARY OF .THE INVENTION It is an object of the invention to automatize a cutting operation of the aforenoted type, utilizing the regularly varying transparency of the web along the'length thereof.
Briefly stated, according to the invention, as the web is advanced into a position in which the severing path of the cutting device coincides with a line along which the web is to be cut, the change of transparency of the web is photoelectrically sensed and the generated signal is utilized to control the feed of the web and the cutting operation. The web is thus automatically and intermittently advanced; the length of each incremental advancement is dependent of the linear intervals at which severing cuts are to be effected.
The apparatus for practicing the afore-outlined method is designed in such a manner that adjacent one web face there is provided a light source, while adjacent the opposite web face there is disposed a photocell cooperating with the light source. The intensity of the latter, as sensed by the photocell, is controlled by the transparency of the interposed, traveling web. The photocell, in turn, controls flip-flop circuits, the outputs of which correspond to different values of light transparency.
The invention will be better understood, as well as further objects and advantages will become more apparent, from the ensuing detailed specification of a preferred, although exemplary, embodiment taken in conjunction with the drawing.
BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a schematic plan view of one part of the embodiment, wherein, for the sake of clarity, the web is displaced transversally to expose components disposedthereunder; and
FIG. 2 is a circuit diagram of the embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, the web to be severed is formed of serially arranged individual, successive photographs 11, ll, 11", etc. spaced from one another by blank strips 12, 12, etc. The dimension L of each photograph measured in the direction of the web travel indicated by arrow 13, is identical, whereas the dimensions 1, 1' of strips 12, 12', respectively (also taken in the direction of the web travel), usually differ from one another. Each photograph has a dark peripheral margin 14. Thus, the blank (light) strips l2, 12, etc., on the one hand, and the margins 14, on the other hand, have values of light transparency which substantially differ from one another.
The web 10 is advanced in the direction of arrow 13 on a table 15 on which there is mounted a cutting device schematically shown at C, adapted to sever the web 10 along a linear, transversal cutting path 16. The dimension B of the web 10 measured transversely to the direction 13 of the web travel remains unchanged by the severing operations.
In order to obtain a uniform size of LXB as a result of the sequential cutting operations, each photograph 11,11, 11'', etc. has to be cut out from the web 10 by severing along respective leading edges 11a, 11a, 11a", etc. and respective trailing edges 11b, 1 lb, etc.
The control of the web feed in the direction of arrow 13 and the control of the cutting operation is effected by an electronic circuitry (generally indicated at 17 in FIG. 2) which senses the aforenoted light and dark conditions of the vweb 10 at predetermined locations on table 15. For sensing said light" and dark" conditions of the web 10, there is arranged thereabove a number of light sources (not shown) with each of which there is associated a photocell disposed beneath the web 10. This embodiment, as shown in FIG. 1, comprises two sensing stations generally indicated at 18 and 19, respectively, disposed upstream and downstream of the severing path 16, at a distance L therefrom. The sensing station 18 comprises a first group of three photocells 20 and an immediately adjacent second group of three photocells 21. Photocells within each group are arranged in a series extending transversally of the direction of web feed, and are thus disposed parallel with the cutting path 16. The two groups of photocells are spaced from the cutting path 16 in such a manner that when the leading edge 11a of the leading photograph 11 coincides with the cutting path 16, as shown in FIG. 1, the photocells 20 of the first group are immediately upstream of, and the photocells 21 of the second group are immediately downstream of, the trailing edge 11b of the first photograph 11. Stated indifferent terms, the first and second groups of photocells of the sensing station 18 are disposed on opposite sides of the trailing edge 11b which forms the borderline between the dark margin 14 of the leading photograph 11 and the immediately following light strip 12. It is thus seen that in order to ensure that the web 10 assumes a correct position for the execution of a severing operation along the leading edge 11a, the photocells 21 have to sense a dark condition and the photocells 20 have to sense a light condition.
The provision of a plurality of photocells (each having its own associated light source) in each group instead of a single one, is advantageous in practically eliminating the possibility of generating false signals, since a signal from any of said groups is emitted only if each photocell in one group senses a transparency of identical value.
The sensing station 19 disposed at a distance L downstream of the cutting path 16 comprises only a sole light source (not shown) and photocell 22, which is, in general, sufficient to emit an unambiguous signal since at this station merely the change from light to dark" has to be sensed. This event occurs when the leading edge 11a of the leading photograph 11 reaches the second sensing station 19- and passes over photocell 22. In this position of web 10, the dark marginal portion 14 disposed immediately upstream of the leading edge 11a, is located between photocell 22 and its associated light source and the trailing edge 11b of the first photograph 11 coincides with the severing path 16 of the cutting device.
In summary, the sensing station 18 serves to determine the position of the leading edge of each photograph along the cutting path 16, whereas the sensing station 19 is actuated when the trailing edge of the same photograph is in a cutting position.
It is to be noted that the arrangement of sensing stations 18 and 19 upstream and downstream of the cutting path 16 is particularly advantageous to secure a uniform L B size of cut photographs despite nonuniform spacings 1, 1', etc.
Further, the provision of two adjacent groups of photocells within sensing station 18 to sense, respectively, a dark and a light field separated by a trailing edge 11b, 11b, etc. is advantageous for particularly accurately sensing the separating line between the last-named dark and light fields.
It is to be understood that any other arrangement of the sensing stations with respect to the severing path 16 is feasible within the scope of the invention.
FIG. 2 illustrates the circuitry generally indicated at 17 which processes the signals from photocells 20, 21 and 22 and, accordingly, controls the web feed and the cutting device. Each photocell 20, 21 and 22 is connected in series between two voltages, with a matching potentiometer 23, 24 and 25, respectively. The output of each photocell sets, through a Schmitt-trigger 26, 27 and 28, respectively, a flip-flop circuit 29, 30 and 31, respectively. Each flip-flop circuit, as known per se, is adapted to assume two stable positions (hereinafter called L"- .and O-positions; with each position there is associated an output (hereinafter called L- and O"-outputs), one of which signals the dark" condition, while the other indicates the light condition.
In case of a light condition, a voltage appears at the L- outputs of the flip-flop circuits 29, and in case of a dark condition, a voltage appears at the O-outputs of the flip-flop circuits 30 and 31. All outputs of the flip-flop circuits 29 and 30 are applied to an AND-gate 32. To the output side of the latter there is connected the flip-flop circuit 31 associated with the sensing station 19 and an OR-gate 33. Further, the output of the flip-flop circuit 31 is connected to the input side of the OR-gate 33.
To the output side of the OR-gate 33 there is connected, on the one hand, through an AND-gate 34 a relay 35 controlling the cutting device and, on the other hand, a further flip-flop circuit 36. The O-output of the latter is connected with a relay 37 actuating a breaking mechanism schematically indicated at Br preferably of the attracting magnet-type, while the L-output of the flip-flop circuit 36 is connected with a relay 38 for controlling the conveying mechanism schematically indicated at CM which advances the web 10. Further, across a switch 39, which is controlled by the relay 37, the O-output of the flip-flop circuit 36 is connected to a second input of the AND gate 34.
Further, means may be provided to apply start and stop pulses to the inputs of the flip-flop circuit 36. Also, to a further input of the flip-flop circuit 36 a standby signal may be applied.
OPERATION OF THE EMBODlMENT First, by means of a starting pulse, the flip-flop circuit 31 is readied and the flip-flop circuit 36 is set into its L-position. Thereby, through relay 38, the conveying mechanism CM for the web is set into motion. As soon as the web 10 has reached its position shown in FIG. 1, the flip-flop circuits 29 connected to the output of the photocells are set into their L-position and the flip-flop circuits 30 connected to the output of the photocells 21 are set into their O-position. At the L- and O-outputs, respectively, of the two aforenoted groups of flip-flop circuits, a voltage appears which generates a voltage at the output of the AND-gate 32. The last-named voltage, on the one hand, readies the flip-flop circuit 31 for the successive sensing step in which the leading edge 11a of the photograph 11 will cover the photocell 22, and, on the other hand, generates a voltage at the output of the OR-gate 33. This lastnamed voltage, on the one hand, readies the AND-gate 34 and, on the other hand, sets the flip-flop circuit 36 into its O- position. Thereby, the relay 37, associated with the braking mechanism Br, is energized and through relay 38 the conveying mechanism CM for the web 10 is deenergized. The relay 37 closes the switch 39 so that a second voltage is applied to the input side of the AND-gate 34. By virtue of the latter occurrence, the relay 35 is energized and thus actuates the cutting mechanism C which severs the web 10 along the leading edge 11a of the photograph 11. Upon completion of the cutting operation, a standby signal, which may be triggered by the cutting mechanism, resets the flip-flop circuit 36 into its L- position whereby the relay 38 is again energized and thus the conveying mechanism CM restarted to again advance the web 10. This conveying operation ends when the leading edge 11a, precedingly severed along line 16, reaches the sensing station 19 and there passes beyond the photocell 22. At that moment, the photocell 22 senses dark and the flip-flop circuit 31 is set into its O-position and another cutting operation is effected by a sequence as described hereinbefore. At this time, the trailing edge 11b of the photograph 11 coincides with the cutting line 16, so that during the aforenoted second cutting operation, the web 10 is severed transversally along trailing edge 11b. As a result of the two cutting operations, the photograph 11 is, in exact LXB size, separated from the web 10.
The subsequent conveying operation ends at the moment when the trailing edge 11b of the second photograph 11' reaches the sensing station 18 and is disposed between the two groups of photocells 20 and 21. Thereafter, the abovedescribed cycle is repeated for cutting out the second photo graph 11' and then the third photograph 11", etc. It is thus seen that the web 10 of indefinite length is cut alternately, on the one hand, into portions of identical size LXB corresponding to the individual photographs and, on the other hand, into waste strips of the size IXB, l'XB, etc.
That which I claim is:
1. An apparatus for actuating a cutting mechanism to effect, along a cutting path, a transversal severance of a web of indefinite length advanced in the longitudinal direction thereof, said web including along its length alternately repetitive adjacent fields of two types having two substantially differing values of transparency, the border line between two adjoining fields of said two types extending transversally of the length dimension of said web, said apparatus comprising,
A. at least one sensing station including at least one first photocell and at least one second photocell; said first and said second photocells being disposed adjacent one face of said web and juxtaposed with respect to one another in the longitudinal direction of said web; said first and second photocells being spaced from said cutting path to such an extent in said longitudinal direction as to be located at different sides of said border line when the desiredline of severance on said web coincides with said cutting path, and
B. electronic circuit means adapted to receive transparency-responsive signals from said sensing station and to actuate said cutting mechanism when a change of transparency is sensed, said electronic circuit means including a flip-flop circuit associated with each sensing station, each flip-flop circuit adapted to receive said signals and deliver two outputs corresponding to said two substantially differing values of transparency.
2. An apparatus as defined in claim 1, wherein a plurality of said first photocells forms a first group of photocells arranged in a juxtaposed series extending parallel to said cutting path and a plurality of said second photocells forms a second group of photocells arranged in a juxtaposed series extending parallel and immediately adjacent to the series of photocells of said first group, said first and second groups are located at different sides of said border line when the desired line of severance on said web coincides with said cutting path of said cutting mechanism.
3. An apparatus as defined in claim 1, wherein fields of one type have identical predetermined lengths in the longitudinal direction of said web, including A. a first sensing station disposed upstream of said cutting path at a distance therefrom corresponding to said predetermined length to sense a change from the transparency of one type of field to the transparency of the other type of field when a desired first line of severance on said web coincides with said cutting path, and
B. a second sensing station disposed downstream of said cutting path at a distance therefrom corresponding to said predetermined length to sense the passage of the leading edge of said web when a desired second line of severance on said web coincides with said cutting path; said leading edge is formed by a'cut coinciding with said first line of severance; the distance between the first and second lines of severance is identical to said predetermined length.
4 An apparatus as defined in claim 1, including an AND- gate to which the output of each of said flip-flop circuits is applied, the output voltage of said AND-gate is adapted to effect the interruption of the web feed and the actuation of said cutting mechanism.
5. An apparatus as defined in claim 3, including an AND- gate to which the output of at least one flip-flop circuit associated with said firstsensing station is applied, the output of said AND-gate is coupled with the input of the flip-flop circuit associated with said second sensing station; the output of said AND-gate is also coupled with an input of an OR-gate, another input of the latter is connected to an output of the last-named flip-flop circuit; the output of said OR-gate is adapted to effect the interruption of the web feed and the actuation of said cutting mechanism.
6. An apparatus as defined in claim 5, wherein the output of said OR-gate is applied to an additional flip-flop circuit, one output'of which is connected with a control means of a braking mechanism, the other output of which is connected with a control means associated with a conveying mechanism for the web feed.
7. An apparatus as defined in claim 6, wherein the output of said OR-gate is also applied to an additional AND-gate, the output of which is connected with a control means associated with said cutting mechanism. I
8. An apparatus as defined in claim 7, wherein an input of said additional AND-gate is connected through a circuit breaker switch to that output of said additional flip-flop circuit which is connected to the control means of said braking mechanism; said circuit breaker switch is adapted to be closed by the last-named control means upon energization thereof by said additional flip-flop circuit.