Apparatus For Intermittent Processing For Web Materials

Abstract

An apparatus for intermittent processing of web material includes means for effecting alternate material feed and material processing operation. The web of material to be processed is supplied by material supply means to the processing means via a generally U-shaped loop portion the lower end of which is detected by photoelectric detector. The apparatus further includes control circuit means which are electrically connected to the photoelectric detector such that the control circuit may actuate processing means into initiating the cycle of feed and processing operation each time the photoelectric detector senses the lower end of the looped web portion. The control circuit also brings supply means out of operation when the photoelectric detector continues to sense the lower end of the looped web portion for a predetermined period of detecting time.

Description

BACKGROUND OF THE INVENTION

This invention relates to apparatus for effecting various processing operations on a web of material. More particularly, this invention relates to apparatus for effecting an alternate feed and cut operation on a web of material being supplied at a fixed speed.

An apparatus for carrying out processing such as, for example, cutting, punching, printing on a web of material such as paper, cloth and the like generally includes means for continuously supplying the web of material to a processing location at a predetermined fixed speed. Where the processing desired is a cutting, there is provided at the processing location cutter means for severing the web material into pieces of a fixed or varying lengths and feeding means for moving the web material supplied from supply means to cutter means.

In this type of web processing apparatus, it is a common practice to store a relatively large amount of the web material at a location between web supply means and web cutting means. The amount of the web material being stored at the storage location is constantly detected by making a rough measuring of its weight. Cutter means at the processing location is kept under a continuous operation until the amount of the stored web material is reduced close to a predetermined level. When the amount of the web material falls below the level, cutter means is held out of operation until the fresh web material is again stocked to the predetermined amount. In such a conventional apparatus, a continuous operation of cutter means is obtained when the web material is being cut into pieces of a minimum allowable length, i.e., the shortest length that can be cut by the particular apparatus. When desired to cut the web material into pieces of a length greater than the minimum allowable length, the web material is "consumed" or cut off in an average amount greater than the amount of the fresh web being supplied at a fixed rate resulting in a shorter operating period of the cutting device followed by a longer inoperative period. Such discontinued and nonuniform operation tends to cause a wear-out of various moving component parts of the cutting device in a relatively short period of time, which in turn causes a considerable reduction in the cutting accuracy. The earlier wear-out of the component parts also shortens the effective operating life of the cutter device. Also, in conventional cutting apparatus, since a relatively large amount of web material is stored at a position in front of the cutting device, the stored web material tends to be twisted or tangled obstructing a ready and smooth feeding thereof to the cutting device. The twisting of the stored web material also tend to damage or impair the material. Furthermore, in case where the web material to be processed is an information carrying tape or the like moved out of an output end of an information producer, a processing of the information carrying tape is delayed to a considerable extent impairing the instantaneous processing requirement.

Another important disadvantage of the conventional apparatus for the web processing resides in the difficulty of selecting and changing the desired processing points along the web of material being supplied.

SUMMARY OF THE INVENTION

Accordingly, a general object of this invention is to provide a new and improved apparatus for the intermittent processing of web materials which is entirely free of the above disadvantages of the prior apparatus.

A particular object of this invention is to provide a new and improved apparatus of the type described for the intermittent processing of web materials wherein means for effecting the desired intermittent processing on the web material is capable of conducting a material feed and processing cycle of operation in a substantially continuous manner.

Another object of this invention is to provide a new and improved apparatus of the type described wherein the amount of the web material stored between web supplying means and web processing means is kept substantially at a predetermined fixed amount.

Another object of this invention is to provide a new and improved apparatus of the type described wherein the operational cycle of web processing means is controlled in accordance with the operation of web supplying means.

Another object of this invention is to provide a new and improved apparatus of the type described which is economically manufactured and is easy to operate. A further object of this invention is to provide a new and improved cutting means for use in the apparatus described which enables a ready and easy selection of cutting positions on the web of material by a simple adjustment of the distance through which the web of material travels after an associated cut mark is sensed and before the web is brought to a halt.

A further object of this invention is to provide a new and improved cutter means for the apparatus described which is capable of keeping the abovementioned web travel distance at a preselected value by controlling the time and speed of the web travel.

Briefly described, the foregoing objects of this invention are fulfilled in an apparatus which generally comprises means for effecting an intermittent processing on a web of material and means for supplying the web of material toward processing means. This processing means includes a driving source of a variable speed type and is adapted to be driven thereby to alternately conduct material feed and material processing actions. The web material is permitted to depend under its own weight in the general form of U-shaped loop at a position between web supply means and web processing means. Means with no moving contact is also provided to detect the lower end portion of this looped web when it moves down to a predetermined lowermost level. Detecting means is electrically connected to a control circuit for the apparatus which controls specifically the movement of web processing means and additionally the movement of web supply means. Each time when detecting means senses the presence of the lower end of the looped web portion at the predetermined lowermost position, the control circuit actuates web processing means which starts one cycle of feed and processing operation. In case the lower end of the looped web portion stays at or below the predetermined lowermost position, detector means applies a signal to the control circuit, upon the receipt of which the control circuit puts supply means inoperative resulting in an interruption of the supply of fresh web material.

With the above described arrangment of the apparatus, the average operational speed of web processing means (under a continuous operation) with respect to the web supply speed is such that the average position of the lower end of the loop will generally be kept slightly above the predetermined lowermost level. Under this condition, the lower end of the loop is raised above the predetermined level at the end of the feed-and-processing cycle in processing means, while the lower end is permitted to move down to a position close to the predetermined level. Thus, the inoperative period of processing means between the end of one cycle of feed-and-processing operation and the beginning of another operational cycle is reduced to such a minimum extent that processing means could be regarded to such a minimum extent that processing means could be regarded as operating substantially in a continuous fashion. With the average feed and processing speed of processing means being selected as above, even if the fresh supply of the web material is accidentally or intentionally ceased processing means is automatically brought to a halt at the end of the particular feed-and-process cycle. When the fresh supply is resumed, the operational cycle of processing means is also restarted. It may, therefore, be possible to control the feed-and-processing operation of web processing means in relation to the operation of web supply means. In addition, if the average operational speed of web processing means is erroneously set below the web supply speed or if the operation of web processing means is brought to a halt due to various causes, the lower end of the U-shaped loop continues to move down as the fresh web is being supplied. However, in the above arrangment of the apparatus, the supply of the fresh material is stopped at the end of a preset time interval after the lower end first reached to the predetermined lowermost position, thus avoiding an excess expansion of the looped web portion. As the result, a stable operation is assured for an extended period of time.

According to this invention, means is also provided for a ready adjustment of processing points on the web of material. This comprises an integration circuit having a variable resistor and a capacitor, and signal amplifying means of a specific operational characteristic. The construction and operation of processing point selector are such that the processing point at which the web is processed may suitably selected by a mere adjustment of the variable resistor.

A D.C. voltage which is a function of the feed-and-processing operation is applied to the capacitor for charging, while amplifying means provides a control signal only when applied with a D.C. voltage of a preset level. The capacitor and amplifier means cooperate to keep the desired processing point as selected by the variable resistor regardless of the varying feed-and-processing speed.

In the following description, the present invention is explained having a particular reference to web cutting operation without necessarily limiting the scope of invention thereto. It should be kept in mind that the present invention is also applicable to any other web processing operations such as, for example, punching, printing, coating, folding, and bending.

BRIEF DESCRIPTION OF THE INVENTION

For a better understanding of this invention, reference may be had to the accompanying drawings wherein like reference numerals have been used to denote identical parts.

FIG. 1 is a schematic illustration of web cutting apparatus embodying the invention;

FIG. 2 is an enlarged partial view showing a photoelectric detector for sensing cut marks on the web of material and web cutting blades included in the apparatus of FIG. 1;

FIG. 3 is a schematic electrical diagram of a control circuit for the apparatus of FIG. 1;

FIG. 4A is a schematic diagram showing more clearly various components of a delay timer included in the control circuit of FIG. 3;

FIG. 4B is a schematic illustration showing voltage vs. time curves in connection with the delay timer of FIG. 4A;

FIG. 4C is a schematic illustration showing the manner in which an amplifier included in the delay timer of FIG. 4A operates.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the attached drawings the present invention is illustrated as embodied in an apparatus for intermittent cutting of a lengthy web material such as paper, cloth or the like into pieces of a fixed or varying lengths. The web cutting system of the illustrated embodiment includes a supply roller 10 at a supply section I which is adapted to be driven by a supply motor SM for moving a web material 12 to a web cutting section generally designated at III. Positioned opposite to and adjacent to this supply roller is a nipping roller 14 which is normally held in pressure engagement on the supply roller 10 with the web of material therebetween. When the supply motor SM is operated, the web material 12 is fed from the supply section I through a plurality of guide and tension bars 16, 18 and 20 onto a horizontal table 22 at the cutting section III. At the cutting section, there is also provided a pair of rollers 24 and 26 similar to the rollers 10 and 14 at the supply section I. These roller are located on opposite sides of the table 22 in face-to-face relation. One roller 24 is fixedly positioned on the lower side of the table in contact with the web material thereon but is rotatably supported to be driven by a drive mechanism. The other roller 26 is also rotatably supported on the upper side of the table and is movable between a position resiliently engaging the lower roller 24 and a position away from the roller. The upper roller 26 is operatively connected to a magnetically actuated solenoid SO and the movement of the roller to and away from the lower drive roller 24 is effected by means of the solenoid SO upon receipt of predetermined electrical control signals as hereinafter explained in detail.

The mechanism for driving the lower roller 24 includes an drive motor DM and a fly wheel 28 mounted on a shaft 30 of the motor. The drive motor DM is connected in driving engagement with the lower roller 24 through a power transmitting gear train 32. This mechanism also provides driving power for a cutter device positioned behind the pair of rollers 24 and 26 in the direction of the movement of the web material. The cutter device comprises a cutting blade 34 which fixedly mounted to the rear end of the table 22 and a movable cutter blade 36 which is supported for upward and downward movements with respect to the fixed blade. More specifically, the movable cutter blade 36 is pivotally mounted to a fixed location by a support arm 38 which in turn is connected by a connecting rod 40 to a crank arm 42. A shaft 44 of the crank is joined to the drive shaft 30 of the motor DM via suitable electromagnetic brake means BR and clutch means CL. Electromagnetic clutch means CL is adapted to selectively bring the crank shaft 44 into and out of engagement with the motor shaft 30, while brake means BR is adapted to selectively arrest the the rotating motion of the crank shaft 44 when the latter is disengaged from the motor shaft. Operation of both brake and clutch means are under control of a control circuit for the entire system which will later be explained in more detail. As the crank shaft 44 is brought into connection with the rotating drive shaft 30 of the motor DM, the crank arm 42 is driven to rotate. The rotation of the crank arm imparts a reciprocating motion to the connecting rod 40 which in turn causes a reciprocating upward and downward movement of the movable cutter 36 via the pivotally mounted support arm 38. In order to detect an upper dead point of the crank arm 42, i.e., an upper most position of the connecting point between the crank arm and the connecting rod during the rotation of the crank arm, there is provided a position detecting proximity switch PX and a switch actuating cam 46. The switch actuating cam is fixedly mounted on the crank shaft 44 such that it may bring the proximity switch PX into an ON position when the crank arm 42 reaches its upper dead point for the purpose hereinafter described. Also connected to the drive motor DM for rotation therewith is a tachometer generator TG which produces a D.C. voltage in direct proportion to and indicative of the rotational speed of the motor.

As described above, the rotational movement of the drive motor DM is transmitted to the web drive roller 24 via the gear train 32 to rotate the same. It should be noted at this point that if the solenoid SO is energized to bring the nip roller 26 in resilient pressure engagement with the rotating drive roller 24 against the biasing force of a coil spring 48, the web of material which has been transported from the supply section I onto the horizontal table 22 is grapsed between the rollers 24 and 26 and is further carried toward the cutting position where the web material is severed into pieces of predetermined lengths by the cutter blades 34 and 36. The running speed of the web material at the cutting section III is determined by the rotational speed of the drive motor DM which is of variable speed type having associated therein a speed controller 60 (see FIG. 3). On the other hand, the cutting motion of the movable blade 36 is controlled by cut marks printed or otherwise applied to the upper surface of the web material in spaced relation along the longitudinal length thereof. In order to detect the cut marks on the web, a photoelectric detector PD is disposed between the pair of rollers 24 and 26 and the cutting blades 34 and 36 and is adapted to actuate the movable cutter blade 36 at the end of a predetermined time interval after it has sensed a cut mark.

As illustrated in FIG. 1 the web of material is largely slackened to downwardly depend in the general form of U-loop 50 between the supply section I and the cutting section III, thereby forming a material storage section II. Since the supply roller 10 is driven at a predetermined fixed speed, the position of the lower apex or end 52 of the U-shaped loop 50 with respect to the horizontal table 22 depends on the relative amounts of the web material delivered at the supply section I and processed at the cutting section III, respectively.

As illustrated in FIG. 1, there is provided at the storage section II means for sensing the position of the lower apex 52 of the U-shaped web section 50. This sensing means comprises a suitable light source such as an electric lamp LA and a photoelectric switch means PS. The lamp LA and the photoelectric switch PS are disposed in alighment at a predetermined position which is a maximum allowable lowermost position for the loop 52. If an excess amount of the web material is stored at the section II sufficient to bring the lower apex 52 of the looped web portion 50 below the allowable lowermost position, the photoelectric switch PS senses this undesirable situation and provides the control circuit of the apparatus with suitable signals for controlling and correlating the feed-and-cut operation at the cutting section III and the web supplying operation at the section I, thereby to achieve a maximum uninterrupted operation of the present apparatus.

Referring now to FIG. 2-3, in particular, and having reference to FIG. 1, a circuit for controlling the web processing apparatus of this invention is described in detail.

In order to initiate the operation the illustrated apparatus, a main switch MS for the circuit leading to a suitable A.C. power source ES and a switch S.sub.1 for controlling the supply motor SM are both closed. The closing of the main switch MS and the motor switch S.sub.1 energizes the supply motor SM and the web of material is fed through the supply roller 10 and the nip roller 14 at a predetermined fixed speed. The closing of the main switch MS also energizes the drive motor DM of the cutting section III and the motor DM in turn drives the lower roller 24 through the fly wheel 28 and the gear train 32. As mentioned hereinabove, the drive motor DM is of a variable speed type and includes a speed controller 60 having a speed adjusting variable resistor R.sub.1. By suitably adjusting the speed controller 60, the rotational speed of the drive motor DM may preferably be selected such that the average web processing speed at the cutting section III will be substantially equal to or slightly greater than the speed at which the web material is supplied from the feed section I.

The control circuit of this apparatus includes a D.C. power supply device D.C. to provide a D.C. power for energizing various D.C. circuit components such as detectros and contactless relay elements. Subsequent to the closing of the main and motor switches, a push button switch PB.sub.1 is depressed to set a flip-flop unit F.sub.1 into an ON position thereby bringing the entire apparatus including the control circuit into operation. Although the drive roller 24 at the cutting section III is already rotated, the web of material on the horizontal table 20 is not yet carried toward the cutting blades since the mating nipping roller is still held out of engagement with the drive roller. Under this situation, the fresh web material 12 is being continuously supplied through the pair of roller 10 and 14 and the newly fed material is stored in the storage section II in the form of a U-shaped loop 50 until the lower apex 52 thereof reaches the predetermined lowermost position. When the lowermost position is reached by the downwardly moving lower apex 52, the light from the lamp LA is shut off bringing the photoelectric switch PS having an amplifier and a Schmidt circuit, both of which are not shown in the drawing, into ON state. The actuation of the photoelectric switch element PS provides an AND circuit A.sub.1 with an input, upon the receipt of which the AND circuit A.sub.1 produces an output for energizing the solenoid SO via a differentiation circuit D.sub.1, a flip-flop element F.sub.2, an AND circuit A.sub.2 and a power amplifier P.sub.2. As the solenoid SO is energized, it brings the nip roller 26 downward into pressure contact with the rotating drive roller 24 to hold the web material on the table therebetween thus initiating the web feeding operation at the cutting section III. As previously explained, a plurality of cut markings are printed or otherwise be applied on the upper surface of the web material spaced predetermined distance away from each other in the running direction of the web. These cutting marks are generally indicative of the positions at which the web material is severed by the cutting device. The photoelectric detector PD is provided to sense the cut marks on the web as they pass directly therebelow. Each time it senses the cut mark, the photoelectric detector PD generates an actuating signal to set a flip-flop F.sub.3 into its ON state via a preamplifier PA with a sensitivity adjusting variable resistor R.sub.2, a polarity selector switch SS and a differentiation circuit D.sub.2. The polarity selector switch SS is included to enable the photochemical detection of both blackish cut marks printed on a white web material and white cut marks applied on a blackish web material. When the flip-flop F.sub.3 is set to ON state, an output potential E of the tachometer generator TG which is in direct proportion to the rotational speed of the drive motor DM is permitted to be applied through a gating circuit G to a delay timer DT for adjusting the desired cutting position of the web material. As shown in FIG. 2, the delay timer DT includes, in addition to the gating circuit G, a Schmidt amplifier SA and an integration circuit which comprises a capacitor C and a variable resistor R.sub.3. The delay timer DT generates an output signal at the end of a preselected delay time t to be supplied through a differentiation circuit D.sub.3 and an OR circuit OR.sub.1 to the flip-flop F.sub.2 clearing it to OFF state. This results in the deenergization of the magnetic solenoid SO and the nip roller 26 is allowed to be urged away from the drive roller 24 by the biasing force of the coil spring 48. In this manner, the feeding of the web material at the cutting section III is brought to a temporary halt with the passage of the preset delay time t after the photoelectric detector PD has sensed a cut mark on the web surface. It should be noted that at this moment the sensed cut mark of the web has been moved to and located precisely at the cutting position directly beneath the movable cutter blade 36 as will be more clearly explained later. While on the other hand, the output of the differentiation circuit D.sub.3 is simultaneously applied through a flip-flop F.sub.4, and AND circuit A.sub.3 and a power amplifier P.sub.3 to the electromagnetic clutch CL to actuate the same. Upon actuation of the electromagnetic clutch CL, the crank shaft 44 is put into operative connection with the motor shaft 30 and the crank arm 42, which has been stationary at the upper dead point, is driven to rotate (FIG. 1). The rotation movement of the crank arm brings down the movable cutter 36 toward the fixed cutter blade 34 to effect the severing of the web material therebetween.

When the crank arm 42 is again brought back to the upper dead point at the end of one rotation, the cam 46 on the crank shaft engages the proximity switch PX to put into its ON position. The actuated proximity switch supplies an output through an associated amplifier and Schmidt circuit (both of which are not shown) to a differentiation circuit D.sub.4, which in turn applies a reset signal to both the flip-flop F.sub.3 and the flip-flop F.sub.4 for clearing them to their OFF state. Resetting of the flip-flop F.sub.4 to its OFF state deenergizes the electromagnetic clutch CR on the one hand and actuates the electromagnetic brake means BR through a NOT circuit N.sub.5 and a power amplifier P.sub.4 on the otherhand. Thus, a cycle of feed-and-cut operation is terminated at the cutting section III. At the termination of one cycle of feed-and-cut operation, the flip-flop F.sub.4 in its OFF state permits the output of the NOT circuit N.sub.1 to be applied to the AND circuit A.sub.1 thereby restoring the original circuit condition ready to start another cycle of feed-and-cut operation of the apparatus. The same cycle of operation is repeated in this manner each time the photoelectric switch PS is actuated upon detecting the presence of the lower apex of the looped web portion 50, thereby to carry out the desired web processing.

In the illustrated web cutting apparatus, it may occasionally happen that the web material is stored at the storage section II in an excess amount sufficient to bring down the lower apex or end of the looped web portion 50 below the predetermined lowermost level due to an accidental stoppage and malfunction of the feed-and cutting mechanism at the cutting section III or an erroneous lower feed setting at the cutting section relative to the web supply speed at the supply section. The allowable lower level of the looped web is manifested by the presence of cooperating lamp LA and photo switch PS. When the lower end portion 52 of the U-shaped loop reaches this level, it shut off the light from the lamp LA to prevent it from striking the photoelectric switch PS. Under this situation, the photoelectric switch generates and supplies an electric signal via an ON delay element 62, an amplifier P.sub.1 to an electromagnetic relay RY to actuate the same. The actuation of the relay releases a normally closed contact 64 thereby opening the electric circuit to the supply motor SM of the supply section I until such time as the photoelectric switch PS receives light from the lamp LA to allow the contact 64 into its normally closed position through deenergization of the relay RY. With this arrangment, the supply of the fresh web material 12 by the supply motor SM is kept ceased as long as the lower end portion 52 of the U-shaped storage loop 50 shuts the light off the photo switch PS. If a normal feed-and-cut operation is restored at the cutting section III, the excess amount of the web material at the storage section II is gradually fed to and "consumed" at the cutting section, and as the result the lower end of the looped web portion 50 is again carried upward. When the lower end moves above the predetermined lower level, the photoelectric switch PS receives light from the lamp LA and the supply motor SM is again actuated through the closing of the relay contact 64 in a manner as described above. The supply of the fresh web material is thus reestablished. The same is entirely true of the particular occasion where the amount of the web material processed by the intermittent feed-and-cut operation at the cutting station III is relatively smaller than the amount of the fresh web material supplied from the supply section I. More specifically stated, by a suitable adjustment of the rotational speed of the drive motor DM, the average speed of feed-and-cut operation at the section III is preselected such that the average amount of the web material processed or "consumed" at the cutting section III may be substantially equal to the amount of the fresh web supplied from the section I.

A termination switch PB.sub.2 of push button type is provided in the D.C. circuit for selectively terminating the feed-and-cut operation at the section III. When the termination switch PB.sub.2 is depressed while the web of material is being fed at the cutting section III, an electrical signal is applied to both the flip-flop F.sub.1 and the flip-flop F.sub.2 to clear them into their OFF state. The resetting of the flip-flop F.sub.2 to OFF state actuates the electromagnetic solenoid SO and, the material feed at the section III is immediately brought to a halt in a manner as described above. If the termination switch PB.sub.2 is depressed while the cutting of the web material is being carried out at the section III, the particular cutting cycle is allowed to continue through to its end but the succeeding cycle of feed-and-cut operation does not take place since the flip-flop F.sub.1 has been cleared to its OFF state by the depression of the termination switch PB.sub.2. This results in the cessation of feed-and-cut operation at the cutting section III. In the illustrated control circuit, NOT circuits N.sub.2 and N.sub.3 are provided for selective interlocking of the solenoid SO with the clutch CL. In addition, the power amplifiers P.sub.1 -P.sub.3, the flip-flops F.sub.1 -F.sub.4, the AND circuits A.sub.1 -A.sub.3, the NOT circuits N.sub.1 -N.sub.5, the differentiation circuits D.sub.1 -D.sub.4, the OR circuit OR.sub.1, the preamplifier PA and the delay timer DT do not include a moving contact, and therefore constitute the contactless circuit components.

One of the important features of this invention is the provision in the control circuit of the cut position adjuster 66 between the flip-flop F.sub.3 and the differentiation circuit D.sub.3. As briefly explained above, the cut position adjuster 66 is for the suitable selection of the position at which the web is severed off and , as shown in FIG. 4a, it comprieses the gating circuit G connected to the tachometer generator TG, the integration circuit having the variable resistor R.sub.3 and the capacitor, and the Schmidt circuit SA. As hereinabove referred, in the apparatus of the illustrated embodiment cut marks are applied to the upper surface of the web material 12 and the actual cutting of the web by the cutter blades is effected after a preset interval of time t from the time when each cut mark is sensed by the photoelectric detector PD. At the end of the preset time interval t the sensed cut mark has been moved away from the detector PD and the feeding of the web material is brought to a temporal halt to carry out the cutting operation. After which the feeding of the web is resumed carrying another cut mark on the web below the photoelectric detector PD. The cycle is repeated.

As schematically illustrated in FIG. 2, the distance s between the photo detector PD and the cutter blade 36 being fixed, the length of the cut pieces of the web depends on the distance a through which the particular cut marks is permitted to run after it has been sensed by the detector and before the web feeding is temporarily stopped. The running or travel distance a is in turn dependent on both the web feed speed and the delay time t. The cut position adjustor 66 according to this invention provides means for selecting the travel distance a which is a function of the length of a cut piece. Once the travel distance is preselected by the cut position adjustor 66, the adjustor itself functions to keep this preselected distance regardless of the web feed speed through a corresponding control of the delay time t.

To state more specifically the operation of the cut position adjustor 66, as the photoelectric detector PD detects a cut mark passing therebelow the flip-flop F.sub.3 is first set to its ON state and the gate circuit G is then conducted permitting the D.C. output potential E of the tachometer generator TG to be applied through the variable resistor R.sub.3 across the capacitor C. Thus, the charging of the capacitor C begins and its charging level gradually rises. However, the Schmidt amplifier SA connected to the integration circuit of R.sub.3 and C is of such operating nature that it provides an output only when it receives an input having a potential of Ea as shown in FIG. 4c. In other words, the Schmidt amplifier SA does not operate until the capacitor C of the integration circuit is charged the same voltage level of Ea. As the capacitor is charged to this level, the charged potential is applied to the amplifier SA causing the latter to produce an output signal. The period between the time when the capacitor C is first charged and the time the capacitor is finally charged to the desired voltage level of Ea corresponds to the above mentioned delay time t, i.e., the time it takes before the cut mark on the running web is stopped after it has been sensed by the photo detector PD.

As can be understood from the voltage time curves of FIG. 4b, the delay time t varies in inverse proportion to the voltage level E and in direct proportion to the time constant T which is equal to R.sub.3 .times.C. This relation can be expressed as follows:

t .varies. T/E = (R.sub.3 .times. C)/E

Since the voltage E produced by the tachometer generator is directly proportional to the rotational speed of the drive motor DM, it is also in exact proportion to the running or feed speed of the web along the horizontal table 22. To take this relation into consideration, the above formula can be rightly changed to:

t .varies. R.sub.3 /v

FIG. 2 shows illustratively a position of one cut mark 80 on the web relative to the photo detector PD and the movable cutter 36 when it is stopped after passing through the detector. The distance between the sensing point of the photo detector PD and the cut mark 80 is indicated at a, which is the distance the cut mark in question travels before it is stopped after sensed by the detector. The alphabetical letter b shows the distance between the particular cut mark 80 and the cutter position at which the web is to be severed off. The letter s indicates the distance between the cutter position and the sensing point of the photo detector. The distance s is fixed.

The travel distance a depends on the web feeding speed v and the delay time t, thus a = vt. Taking this relation into the above formula, it is expressed as follows:

a .varies. v .times. (R.sub.3 /v) = R.sub.3

As is apparent from this formula, the travel distance a may suitably be selected independent of both the feed speed v and the delay time t by merely changing the value of the variable resistor R.sub.3 in the integration circuit. The distance b between the cutter position and the sensing point of the photo detector being fixed, a change in the travel distance a of the cut mark 80 inevitably causes a corresponding change in the distance s which is the distance between the cut mark and the cutter or cutting position resulting also in a change of the distance between the new cut position and a leading cut end of the web, the leading end being the position at which the web is severed during a preceeding cycle of feed-and-cut operation. It should be noted that the distance between the leading end of the web and the cutter position is the length of a piece to be cut. In short, the length of a web piece to be formed during a particular cycle of the feed-and-cut operation can readily be selected by merely adjusting the variable resistor R.sub.3 in the integration circuit. In addition, the selection is made independent of the web feed speed and the delay time t.

The cut mark 80 is exemplary illustrated in FIG. 2 as being stopped at a position spaced away from the cutter blade in the normal direction of feed, i.e., a position on the left side of the cutter. However, it is possible through a suitable adjustment of the variable resistor R.sub.3 to select the travel distance a such that the cut mark 80 may be stopped at a position directly below the cutter blade or at a position spaced away from the cutter blade in a direction opposite to the feed direction, i.e., a position on the right side of the cutter as viewed in FIG. 2.

Once the travel distance a of the web material is preselected to a desired value through a suitable adjustment of the variable resistor R.sub.3, then the delay timer 66 functions to keep this preselected travel distance regardless of the varying web feeding speed at the cutting section. This is automatically done by the previously mentioned time delay function of the combination of the capacitor C and Schmidt amplifier SA which controls the delay time t in inverse proportion to the feed speed such that the value of v .times. t may be kept constant at the preselect value.

As is also readily be understood from FIG. 2, the distance b is a deduction of the distance s from the distance a, thus b = a - s. This can be expressed as a = b + s. Now to express a distance corresponding to the distance s but taken from the cutter position in the normal direction of web feed as -s, the range within which the distance b is desired to adjust falls generally within the distance range of +s .about. -s. in actual practice. In such a case, the distance a could be varied within the range from a value corresponding to 2s to zero by suitably setting the cut position adjusting variable resistor R.sub.3 at a value within a maximum resistor and zero. In actual practice, it may preferably be designed that a setting of the variable resistor at a value intermediate the maximum and zero will fix the distance b at zero so that the selection of the distance b at a value within +s.about.-s becomes possible through a suitable adjustment of the resistor R.sub.3.

As is apparent from the foregoing detailed description, once the average processing speed is set at the desired value, the cutting apparatus operates at a minimum possible speed in relation to the preselected cut length of the web making a continued and uninterrupted feed-and-cut operation. Thus, an earlier wear out of the movable component parts of the apparatus due to the discontinued and nonuniform operation is effectively avoided resulting in an accurate feed-and-cut motion for an extended period of time. In addition, the lower end of the looped web portion is kept substantially at the predetermined position with a slightest change in the amount of the stored web. This aids in achieving a higher cutting accuracy as well as an immediate cutting of the web being continuously supplied. The fact that the feed-and-cut cycle at the cutting section III is controllable in connection with the operational condition at the supply section I assures a safe operation of the apparatus under any condition in the section preceeding the cutting or processing section. The fact that the control circuit of the apparatus is comprised of contactless components is also helpful to bring about the various advantages of the present invention. Moreover, according to the control circuit of this invention, the cut position of the web can readily be selected as desired regardless of the web feeding speed. And once the cutting position, thus the length of the severed web piece is preselected, it is automatically maintained irrespective of the varying web feed speed at the cutting section.

Although the invention has been described with reference to a particular embodiment, many modifications, both in form and detail, will occur to those skilled in the art. Accordingly, all such modifications and variations are intended to be included within the scope and spirit of the invention as defined in the claims.

Claims

What is claimed is:

1. A system for controlling apparatus for processing web material comprising:

A. a source of web material which supplies said material at constant speed;

B. processing apparatus for performing a predetermined cycle of operation on the web material;

C. feeding means for directing the web material from the source to the processing apparatus, said feeding means causing said material to move in a path having a depending loop between said source and said feeding means;

D. first sensing means responsive to the length of the loop to generate a signal which actuates the feeding means;

E. second sensing means located in the path of the material and responsive thereto to generate a signal according to the position of the material;

F. a control circuit which is energized by the position signal to stop the feeding means and activate the processing apparatus after a predetermined delay; and

G. switching means actuated by the conclusion of the processing cycle to reset the control circuit for subsequent cycling.

2. A system for controlling apparatus for processing web material as described in claim 1 wherein the feeding means comprise:

A. a feed roller for moving the material towards the processing apparatus when said material is in engagement with said roller;

B. an idler roller normally being in a position to urge the material into engagement with the drive roller, but being movable to a second position which disengages the material from the drive roller; and

C. a solenoid operatively connected to said idler roller to move said roller from its normal positions to its second position in response to the control circuit, thereby stopping the material feed.

3. A system for controlling apparatus for processing web material as described in claim 1 wherein the first sensing means comprises:

A. a source of light; and

B. photosensitive means responsive to the light source, and being positioned so that the depending loop of material will interrupt said light source when said loop attains a predetermined length.

4. A system for controlling apparatus for processing web material as described in claim 1 wherein the second sensing means comprises a photoelectric switch which is responsive to marks placed on the material at predetermined intervals.

5. A system for controlling apparatus for processing web material as described in claim 1 wherein the control circuit comprises:

A. a delay timer which generates a signal after a predetermined time has elapsed from said timer's energization;

B. means for generating a potential which is proportional to the speed of the feeding means;

C. means responsive to the position signal to apply the potential to the delay timer causing energization thereof; and

D. means responsive to the signal from the delay timer to stop the feeding means and actuate the processing apparatus.

6. A system for controlling apparatus for processing web material as described in claim 1 wherein the processing apparatus comprises a cutter device.

7. A system for controlling apparatus for processing web material comprising:

A. a source of web material which supplies said material at a constant speed;

B. processing apparatus for performing a predetermined cycle of operation on the web material;

C. a feed roller for moving the web material towards the processing apparatus when said material is in engagement with said roller, said roller causing said material to move in a path having a depending loop between said source and said feed roller;

D. an idler roller normally being in a position to urge the web material into engagement with the feed roller, but being movable to a second position which disengages the material from the feed roller;

E. a solenoid operatively connected to said idler roller to move said roller from its normal position to its second position;

F. a source of light situated in the path of the depending loop;

G. photosensitive means responsive to the light source and being positioned such that the depending loop of material will interrupt said light source when said loop attains a predetermined length, thereby generating a signal which actuates the idler roller solenoid to its normal position;

H. a photoelectric device which is responsive to marks placed on the material at predetermined intervals to generate a signal;

I. a delay timer which generates a signal after a predetermined time has elapsed from said timer's energization;

J. means for generating a potential which is proportional to the speed of the feed roller;

K. first switching means responsive to the signal of the photoelectric device to apply the potential to the delay timer causing energization thereof;

L. second switching means responsive to the signal from the delay timer to stop the feeding means and actuate the processing apparatus; and

M. third switching means actuated by the conclusion of the processing cycle to reset the delay timer and the first and second switching means for subsequent cycling of the processing apparatus.

8. A system for controlling apparatus for processing web material as described in claim 7 wherein the processing apparatus comprises a cutter device.