US 3816210 A
The present invention provides a method of and apparatus for automatically controlling longitudinal transfer of a plurality of film strips in a bag-making machine, packaging machine, or the like. One of the most important features of the method is that, when one of the strips goes ahead of the other strip or strips, the feeding of all the strips is stopped by braking an intermittent conveyor means, and the leading preceding strip is braked during the next feeding action of the conveyor means. The apparatus is provided with sequential control units, including photoelectric detectors, for carrying out the method.
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Description (OCR text may contain errors)
United States Patent [191 Aoko et al. June 11, 1974 METHOD OF AND APPARATUS FOR  References Cited AUTOMATICALLY CONTROLLING UNITED STATES PATENTS TRANSFER OF FILMSTRIPS 3,509,095 6/197] James 226/2  Inventors: Seiji Aoko; Akira Kamiyana; Tsugio Yoshida, n f saitama, Japan Primary Examiner-Allen N. Knowles F -M T ttl 73 Assignee: Taiyo Shokai Co., Ltd., Tokyo, Attorney Glew and u 6 P  ABSTRACT  Filed: Dec. 13, 1972 The present invention provides a method of and appa-  Appl' 314533 ratus for automatically controlling longitudinal transfer of a plurality of film strips in a bag-making ma- [3'0'] Fbi-ei h Ab fliiiii Pfi'b it Data" chine, packaging machine, or the like. One of the most important features of the method is that, when Dec. 13. I971 Japan ..46 100876 one of the Strips g ahead of the other strip or p the feeding of all the strips is stopped by braking an  U.S. Cl 156/290, 156/361, 156/583, intermittent conveyor means, and the leading preced- 226/2, 226/4, 226/8, 226/32, 226/109 ing strip is braked during the next feeding action of [Sl] Int. Cl B32b 31/00, B65h 17/42 the conveyor means.'The apparatus is provided with Field of Search sequential control units, including photoelectric detectors, for carrying out the method.
11 Claims, 6 Drawing Figures METHOD OF AND APPARATUS FOR AUTOMATICALLY CONTROLLING TRANSFER OF FILMSTRIPS SUMMARY OF THE INVENTION This invention relates to a method of and apparatus for automatically controlling transfer of a plurality of film strips of a thermoplastic synthetic resin, such as vinyl or polyethylene, as a bag or package material, which are intermittently transferred by an intermittent conveyor means, and more particularly to such method and apparatus that can be applied to a method and machine for manufacturing bags from such material, for packaging articles with the material and/or for printing the same. i
In a conventional method and apparatus in the art, each of two or more such film strips is retarded by an electromagnetically operated braking means, during rotation of the intermittent conveyor means, independently of and without reference to the other strip or strips. With such a way of control, however, it is often required to manually adjust the conveyor means so that the distance through which each strip is intermittently conveyed at one time will correspond to the length of a single bag or package. Such manual adjustment is not only troublesome, but also consumes a considerable time and labor. Moreover, the strips are liable to be longitudinally strained, and heat-sealed portions of the strips are apt to be damaged by the strain, during operation of the machine.
The present invention aims to provide a new method and apparatus which eliminate the inconveniences and drawbacks of such prior art.
According to the present invention, there is provided a method of automatically controlling transfer or transport of a plurality of transversely spaced parallel'film strips in a bag-making machine, packaging machine, printing machine or the like, which comprises the steps of: transferring the film strips, each having register marks at substantially regular intervals, by an intermittently operated conveyor means of a nipper type; detecting the respective marks of the strips by separate photoelectric detectors; stopping all of the strips by braking the conveyor means by means of a first braking device which is arranged to be operated in response to first detection by one of the detectors of one of the marks; and braking only the strip leading the other strip or strips during the next feeding action of the conveyor means by means of a respective second braking device for the strip.
There is also provided by the present invention an apparatus for automatically controlling transfer or longitudinal transport of a plurality of transversely spaced parallel film strips in a bag-making machine, packaging machine, printing machine or the like, which comprises an intermittently operated conveyor means having a pair of nipping rollers and adapted to intermittently convey such film strips, each having register marks at substantially regular intervals, a clutch device mounted on a driven shaft and arranged to couple a shaft of a nipping roller of the conveyor means with the driven shaft, a first braking device mounted on the nipping roller shaft, respective photoelectric detectors provided on the strip-feeding side of the conveyor means and arranged to detect the marks on the associated strips, and second respective braking devices provided on the strip-feeding side of the conveyor means and arranged to brake the associated strips, the first braking device being arranged to be operated to stop rotation of the conveyor means in response to first detection by one of the detectors of one of the marks, the second braking devices being arranged to brake only the strip leading the other strip or strips during the next feeding action of the conveyor means.
BRIEF DESCRIPTION OF THE DRAWINGS The method and the apparatus according to the present invention will now be described in further detail with respect to embodiments in connection with the accompanying drawings in which:
FIG. 1 is a diagrammatic view of one embodiment of the present invention as applied to a bag-making machine,
FIG. 2 is a plan view of the embodiment shown in FIG. 1;
FIG. 3 is a diagrammatic representation, showing one example of logic circuit with control units for a sequential control of the embodiment;
FIG. 4 is a diagrammatic view of another embodiment of the present invention as applied to a bagmaking machine;
, FIG. 5 is a view similar to FIG. 4, showing another embodiment of the invention as supplied to a bagmaking machine; and
FIG. 6 is a time chart, illustrating the process of operation of the apparatus according to the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS Like portions or parts are indicated by like numerals and characters throughout the specification and drawings.
In one embodiment of the present invention schematically illustrated in FIGS. 1 and 2, an intermittently operated conveyor means 11 of a nipper type, which comprises a pair of intermittent rollers 11a and 11b is, provided on the frame 10 of a bag-making machine. The
intermittent conveyor means 1 l is driven by a motor 12 through the medium of a crank mechanism 14 which comprises a main shaft -13 rotated by the motor, a crank 15 fixedly mounted on the main shaft, a crank rod 17 connected at one end to the crank 15 by a pin 16 and at the other end to a segmental gear 18 and a pinion l9 fixedly mounted on a driven'shaft 20 and in meshed'engagement with the teeth of segmental gear 18, driven shaft 20 being in alignment with and connected to the shaft of roller 11a or llb by means of a one-way clutch or free wheel 21 and an electromagnetic clutch-brake assembly 22 which is known per se. The intermittent conveyor means 11 is angularly advanced when an electromagnetic clutch 22a of the assembly 22 is operated.
As the conveyor means 11 is rotated, a plurality of transversely spaced parallel film strips 23a and 23b, as bag materials which are nipped between the two rollers 11a and l lb, are intermittently transferred transported through a certain distance, at each time, corresponding to the length of a single bag. A common welder 24 for the strips 23a and 23b is located on the feeding side of the conveyor means ll, transversely across the strips. A supporting table 25, which constitutes part of the welder 24, is provided beneath the paths of the strips.
A heat-sealer 26 of the welder is located above the paths of the strips and is arranged to be brought into contact, at its welding edge, with the upper surface of supporting table 25, and to be moved away therefrom, at each inoperative interval of the conveyor means 11.
Between the welder 24 and the conveyor means 11 are provided mark detectors 28 and 29, which comprise photoelectric tubes 28a and 29a, or like devices, and lamps 28b and 29b, respectively. These detector means are arranged to detect register marks 27a and 27b (or portions of patterns) indicated on each of the film strips 23a and 23b, respectively. Provided between the detector means and the conveyor means'll, and indicated by numerals 30 and 30, are respective braking devices for braking transfer or longitudinal advance of the strips 23a and 23b. Each of the braking devices includes an electromagnetic means and a spring means and is arranged to brake transfer of the associated strip by pressing it against a surface of a roller 30a. Severing means 41 are provided downstream of conveyor 11 for the purpose of severing the strips into individual bags.
In this connection, it is to be noted that each such braking device may be of a type which is arranged to be operated by electromagnetic force only, or of a type which is arranged to be pneumatically or hydraulically operated. In order to provide such pneumatically or hydraulically operated braking device, it is necessary'to incorporate in the brake proper a pneumatic or hydraulic system, which comprises a cylinder, a pipe line, etc., and an electromagnetically operated valve for operating such system. In the illustrated embodiment, each braking device is constructed such that, when a solenoid of the electromagnetic means is de-energized, the braking action is effected by the action of a spring means, whereby transfer of the associated strip is braked.
The interrelationship between electromagnetic clutch-brake assembly 22, mark detecting means 28 and 29 and braking devices 30 and 30 is diagrammatically shown inFlG. 3.
As shown in FIG. 3, the photoelectric elements 280 and 29a are connected to respective amplifiers 31a and 31b which are connected to the input side of an OR- device 32 which, in turn, is connected to an AND- device 33. Indicated by numeral 35 is a cam which is fixedly mounted on main shaft 13 and which is adapted to operate a switch 36 to transmit a signal therefrom to the AND-device 33, the output side of which is connected to the input side of a flip-flop device 34. In the embodiment shown in FIG. 3, the brake 22b is arranged to be operated, for braking action, when it receives a signal from the AND-device 33. However, until the brake 22b receives a signal from AND-device 33, flipflop device 34 receives, directly from switch 36, a' signal, and causes electromagnetic clutch 22a to be operated for coupling to thereby keep the brake 22b in inoperative position.
The output sides of the photoelectric elements 28a and 29a are connected to input sides of respective AND-devices 37a and 37b in parallel with the OR- device 32, and, to the other input sides of the AND- devices, are connected the output side of switch 36, which is actuated by the cam 35, via erasing devices 42a and 42b. The output sides of AND-devices 37a and 37b are connected to a flip-flop device 38 which is arranged to alternately energize solenoids 40a and 40b of the electromagnetic braking devices 30 and 30 through the medium of a relay device 39. Each AND- devices 37a and 37b is adapted to operate so that a signal entering one of the input sides of the mating device 37a or 37b is erased.
When it is desired to operate the machine shown in FIGS 1 and 2, the two film strips 230 and 23b are nipped between the two rollers 11a and 11b in transversely spaced parallel relationship. In this case, it is desirable that the strips 230 and 23b are arranged so that the register marks 27a and 27b, which are longitudinally equidistantly indicated on the strips, are transversely aligned with each other, approximately. Next, the cam 35 is adjusted so that switch 36 is adapted to actuate brake 22b and braking devices 30 and 30 at the end of each intermittent travel of the strips and that, when the conveyor means 11 is in inoperative position, switch 36 is returned to OFF position.
Then, as the motor 12 starts rotating, the driven shaft 20 is oscillated within a predetermined angular range by means of the crank mechanism 14, and the conveyor means 11 is intermittently driven to convey the strips 23a and 23b intermittently for a certain distance, at each time corresponding to the length of a single bag. During travel the strips, it occurs usually that one of strip goes ahead of the other and the register marks 27a and 27b are brought into disagreement with each other, due to expansion or contraction of the strips, slip difference between the strips nippedand transferred by the intermittent rollers 11a and 11b, etc..
When the strips 23a and 23b arrive at the end of each intermittent travel, switch 36 is operated by the rotating cam 35 and transmits a signal to AND-device 33 as well as to AND-devices 37a and 37b.
'If and when either one of the strips, for example, strip 23a travels, ahead of the other strip 23b and the register mark 27a on strip 23a is detected by the mark detector 28, the signal thereof is transmitted to OR- device 32 after being amplified by amplifier 31a, and then to flip-flop device 34 by way of AND-device 33, whereby electromagnetic clutch 22a is released and electromagnetic brake 22b is actuated to stop rotation of the intermittent conveyor means 11, and, at the same time, the signal from amplifier 31a operates relay device 39, by way of AND-device 37a and flip-flop device 38, to break the circuit of solenoid 40a, whereby, by the action of the returnspring, the strip-braking device-30 is operated to brake transfer of the strip 23a.
Also, at the same time, the signal entering AND- device 37b through erasing element 42b is erased by the output from AND-device 37a. Accordingly, when the photoelectric element 29a detects a register mark 27b on the strip 23b after the other photoelectric element 28a has detected a register mark 27a on the other strip 23a, AND-device 37b does not transmit a signal.
As the main shaft 13 is further rotated, the cam 35 turns switch 36 to OFF position, with its protruding portion, to break the circuit between the switch 36 and the AND-device 33, therebycausing clutch 22a and brake 22b to be coupled and released, respectively. At the same time, the braking action against the strip 23a by braking device 30 is retained, since the flip-flop device 38 is adapted to keep the solenoid 40a de-energized.
However, if and when the photoelectric element 290 first detects a mark 27b, AND-device 37b is operated to open relay 39 and solenoid 40b is de-energized, whereby transfer of strip 23b is braked by braking device 30.
Thus, according to the present invention, when one of the strips 23a and 23b goes ahead of the other, con veyor means 11 is caused to be stopped in response to detection by the detector 28 and 29 of a mark on the preceding strip. Therefore, the section of single bag of the preceding strip 23a or 23b can be accurately processed for the purpose intended. The preceding strip thus processed is retarded, in the next feeding action of the conveyor means 11, by the respective braking device 30 or 30', so that the delayed other strip will recover the delay, whereby the marks 27a and 27b, which have failed to keep pace with each other, are corrected and brought into transversely aligned relationship.
Referring now to FIG. 4, there is shown another embodiment of the invention as applied to a bag-making machine. In this embodiment, an electromagnetic brake 22b is provided instead of the electromagnetic clutch-brake assembly 22 in the first embodiment, and each mark detector 28, 29 is arranged so that it will transmit a signal during rotation of the intermittent conveyor means 11 by inertia after the driven shaft has ceased rotating. The brake 22b is adapted to be actuated by this signal.
The second embodiment has the advantage that the apparatus is simplified by the omission of the electromagnetic clutch, 22a and that the omission of the clutch the slip, disc of which tends to slip enables the intermittent conveyor means 11 to be smoothly rotated without any slippage. Other portions or parts of the second embodiment are the same as those of the first embodiment.
FIG. 5 shows a third embodiment of this invention. In this embodiment, the intermittent conveyor means 11 is driven by motor 12 through the medium of the electromagnetic clutch-brake assembly 22 only. The control of transfer of the strips is automatically effected in the manner similar to that of the first embodiment, that is, by detection of a mark on the preceding or leading strip. This third embodiment is suitable for use in the processing of a strip-like bag material having marks at relatively long intervals. With arrangement, it is impossible to use such a cam such as employed in the previously mentioned embodiments. Accordingly, two photoelectric elements are provided longitudinally along each strip. In this case, the photoelectric elements which are located on the inlet side of the strips transmit control signals for controlling transfer of the strips. A timer is used for the resetting purpose.
What we claim is:
1. A method of maintaining lateral alignment between register marks on transversely spaced film strips, each consisting of a longitudinally folded film or a collapsed tubed of a thermoplastic synthetic resin, during feeding of the strips to a bag-making machine to form bags, said method comprising the steps of intermittently conjointly feeding all the strips to the machine for. formation into bags; individually scanning each strip fed to the machine to detect the respective register marks; responsive to detection of a register mark on one strip in advance of detection of the corresponding register marks on the other strips; interrupting the feed ing of all of the strips; then maintaining said one strip stationary while feeding the other strips; and responsive to lateral realignment of the detected register mark on said one strip with the corresponding register marks on the other strips, again feeding said one strip conjointly with the other strips.
2. A method according to claim 1, including the step of, following such interrupting of the feeding of all of the strips, individually braking said one strip while feeding the other strips; and responsive to lateral realignment of the detected register mark on said one strip with the' corresponding register marks on the other strip, releasing the braking of said one strip'for conjoint feeding of said one strip with the other strips.
3. A method according to claim 1, in which, during each intermittent feeding stroke, the strips are advanced through a distance corresponding to the longitudinal spacing of longitudinally adjacent register marks thereon; and, between the intermittent feeding strokes of each strip, performing the bag formation thereon.
4. A method according to claim 3, in which the bag formation on each strip is effected by a heat sealing operation between successive intermittent feeding strokes.
5. Apparatus for controlling feeding of transversely spaced film strip, each consisting of a longitudinally folded film or a collapsed tube of a thermoplastic synthetic resin, in-a bag-making machine to form bags, while maintaining lateral alignment between corresponding uniformly longitudinally spaced register marks on the strips, said apparatus comprising, in combination, conveyor means, including a pair of pinch rolls adapted to grip said strips and feed the same there through in transversely spaced parallel relation with each other; driving means operable to rotate said pinch, rolls intermittently to effect intermittent conjoint feeding of all the strips; respective scanning means operable to scan each strip, during feeding thereof, to detect the respective register marks; a first braking device operatively connected to said scanning means and selectively operable to brake said conveyor means responsive to detection by said scanning means, of a register mark on one strip in advance of detection of the corresponding register mark on the other strips, to interrupt the feeding of all the strips; respective second braking devices each operatively associated with a respective strip and selectively operable individually to brake the associated strip; means operatively connecting said second braking devices to said scanning means and operable, responsive to detection of a register mark on one strip in advance of detection of the corresponding register marks on the other strips, to actuate only that second braking device associated with said one strip to brake said one strip during the next feeding stroke of said conveyor means conjointly feeding all the other strips; and means connected to said scanning means and to said second braking devices operable, responsive to lateral realignment of the detected register mark on said one strip with the corresponding register marks on the other strips, to deactivate said second braking device associated with said one strip for feeding of said one strip conjointly with the other strips.
6. Apparatus according to claim 5, in which said first braking device is an electromagnetic clutch-brake assembly including an electromagnetic clutch and an electromagnetic brake connected to be alternately operable.
7. Apparatus according to claim 6, in which each second braking device comprises an electromagnetic release means, a return spring and a roller supporting the associated strip; each return spring pressing the associated strip against the surface of said roller, to brake the associated strip, responsive to deenergization of the associated electromagnetic means 8. Apparatus according to claim 5, in which said driving means includes a drive shaft; a driven shaft connected to at least one of said pinch rollers; crank means connecting said drive shaft to said driven shaft for oscillation of said driven shaft responsive to rotation of said drive shaft; and a unidirectional clutch device interposed between said crank means and said conveyor means and operable to rotate said driven shaft intermittently in only one direction responsive to rotation of said drive shaft.
9. Apparatus according to claim 8, in which said first braking device comprises an electromagnetic clutchbrake assembly including an electromagnetic clutch and an electromagnetic brake which are operable in alternation; switch means connected to said electromagnetic clutch-brake assembly and operable to effect such alternate actuation of said electromagnetic clutch and said electromagnetic brake; and cam means on said drive shaft operating said switch means to energize said electromagnetic clutch during a portion of each revolution of said drive shaft and to de-energize said electro magnetic clutch and to energize said electromagnetic brake during the remainder of each revolution of said drive shaft.
10. Apparatus according to claim 9, in which said scanning means comprises respective photoelectric detectors operatively associated with each strip in advance of said conveyor means.
11. Apparatus according to claim 10, including heatsealing means operatively associated with said strips in advance of said conveyor means and operable to heatseal said strips between the intermittent feeding strokes of said conveyor means.