GB2088340A

GB2088340A - Controlling Intermittently Advanced Web During Cutting Off Cigarette Pack Blanks

Info

Publication number: GB2088340A
Application number: GB8133795A
Authority: GB
Original assignee: Hauni Werke Koerber and Co KG
Current assignee: Koerber AG
Priority date: 1980-11-07
Filing date: 1981-11-05
Publication date: 1982-06-09
Also published as: JPS57114411A; IT1140024B; IT8124783A0

Abstract

Cigarette pack blanks are cut from an intermittently advanced web which carries mark(s) (54) to actuate sensor(s) (56, 57) which generate a first signal to decelerate the moving web to a slow speed and then a second signal to halt the web. Either two adjacent marks on the web actuate a single sensor (see Fig. 6), or two photoelectric sensors (56, 57) respond to a single web mark (54), for each blank cut from the web. The control circuit includes a pulse generator (163) ensuring synchronous operation of the feeder/cutter with a packing machine. The web is advanced by a variable speed motor (16) driving nip rollers (12, 13). The web is cut when stationary and the cut blanks are pressed down onto a sloping table at a slightly lower level. The blanks are removed by suction grippers (see Figs. 1-3). The web can be advanced over the previous cut blank on the sloping table. <IMAGE>

Description

SPECIFICATION Blank Forming and Manipulating Apparatus for Cigarette Packing Machines or the Like The present invention relates to packing machines in general, especially to packing machines for cigarettes or like smokers' products.

More particularly, the invention relates to improvements in apparatus for forming and manipulating blanks in cigarette packing and like machines, especially in machines for the making of so-called soft cigarette packs.

A cigarette packing machine comprises means for assembling groups or blocks of arrayed cigarettes which are thereupon draped into several blanks constituting the envelopes or layers of a pack. In a so-called soft cigarette pack, the cigarettes are surrounded by an inner layer which may consist of metallic foil, a median layer of paper or the like, and an outer layer of thicker paper, lightweight cardboard or the like. It often suffices to employ only two envelopes, namely, an inner envelope which is made of tinfoil-coated paper and an outer envelope having an open end which is bridged by a revenue label.The blanks which are to be converted into inner and/or outer envelopes of soft packs are supplied in the form of a continuous strip or web which is subdivided into discrete blanks, and such blanks are thereupon manipulated, i.e., transported toward and draped around hollow mandrels which contain blocks of properly arrayed cigarettes. A web which is to be subdivided into discrete blanks is moved lengthwise by a suitable advancing or transporting mechanism which draws the web off a bobbin or reel and delivers the leader of the web into the range of an intermittently operated severing device. Successive blanks are taken over by a removing mechanism which transfers such blanks to the next processing station, e.g., into the range of a wrapping mechanism which drapes successive blanks around successive mandrels.

As a rule, the web of blanks is provided with indicia which are monitored by a control system serving to ensure accurate positioning of the web with reference to the severing device so that the latter invariably separates a complete blank.

Finished soft packs are normally conveyed into a separate second packing machine which provides each soft pack with a transparent outermost envelope consisting of cellophane or the like. The envelope which is immediately adjacent to the cellophane envelope normally bears printed matter including the trademark or trademarks of the manufacturer, other information pertaining to the manufacturer, the brand name, the customary warning and/or other data. Such information must be readily visible on a finished soft pack, i.e., it is highly desirable to ensure that the web of coherent blanks which are about to be converted into envelopes is severed at predetermined locations so that the location of printed and/or otherwise applied matter on each and every pack is the same.This necessitates accurate guidance of the web on its way from the bobbin or reel to the severing station, accurate positioning of the leader of the web with reference to the cutting plane, and predictable manipulation of successive blanks during transport from the severing station to the wrapping station as well as during conversion of blanks into envelopes of soft packs.

Commonly owned copending application No.

8010579 filed March 28, 1980 discloses an apparatus which transports a web of coherent blanks from a source of supply to the severing station in a cigarette packing or like machine. The means for transporting the web from the source (such as a reel or bobbin) to the severing station comprises two types of transporting means, namely, first transporting means in the form of tongs which transport the web at intervals and through predetermined distances each of which approximates but is slightly less than the length of a discrete blank, and second transporting means in the form of entraining elements having pallets which extend into marginal notches of the web and complete the transport of the web through distances corresponding to the length of a blank.

Such transporting apparatus can advance the web with a reasonably high degree of accuracy and reproducibility. However, they can be used only in connection with the subdivision of certain types of webs, namely, webs whose marginal portions are provided with notches for the entraining elements of the transporting apparatus.

Furthermore, the speed of such transporting apparatus is not entirely satisfactory, especially in modern packing machines which can turn out several hundred soft cigarette packs per minute.

The speed of the just described transporting apparatus cannot be increased at will because a certain period of dwell after completion of the severing operation is necessary in order to allow for removal of the freshly severed or separated blank from the severing or subdividing station, i.e., it is necessary to provide room for the leader of the remaining portion of the web before the web is set in motion subsequent to completion of a severing operation. Still further, the entraining elements are likely to damage or deface the web in the absence of perfect synchronization between their movements and the movements of the aformentioned tongs.

An object of the invention is to provide a novel and improved apparatus for subdividing a continuous web of paper or the like into discrete sections or blanks and for manipulating the thus obtained blanks, especially in a packing machine which confines blocks of cigarettes in so-called soft packs.

Another object of the invention is to provide a packing machine which embodies the above outlined apparatus.

The invention is embodied in an apparatus for converting a web or strip consisting of a series of coherent blanks of identical length into discrete blanks, especially in a packing machine such as a machine for confining blocks of cigarettes or analogous smokers' products in so-called soft packs. The apparatus comprises means for intermittently transporting a web which has an indicium for each of its blanks lengthwise along a predetermined path including variable-speed motor means and means for advancing the web along the path in response to actuation of the motor means, severing means adjacent to a predetermined portion of the path and being operable to separate successive foremost blanks from the web while the motor means is idle, means for removing successive separated blanks from the path, and control means for the motor means.The control means includes means for initiating the actuation of motor means at a first speed upon completion of a severing operation (such initiating means may comprise a pulse generator which is operated by the main prime mover of the packing machine), detector means arranged to scan the web for the presence of indicia and to generate a first signal and thereupon a second signal on detection of the indicium denoting the foremost blank of the web, and means for processing the signals and for transmitting processed signals to the rpotor means so that the first signal effects a deceleration of the motor means from the first speed to a lower second speed before the advancing means completes the transport of the web through a distance equal to the length of a blank and the second signal effects a deceleration of the motor means from the second speed to zero speed at the exact instant when the advancing means completes the transport of the web through a distance equaling the length of a blank.

The advancing means may comprise a first roller, wheel or an analogous rotary member which is disposed at one side of the path and receives torque from the motor means, and a second roller, wheel pr an analogous rotary member which is disposed at the other side of the path opposite the first rotary member and serves to urge the web against the periphery of the first rotary member.

The processing means preferably further comprises means (such as a tachometer generator) for monitoring the speed of the motor means and for generating third signals whose characteristics are indicative of the speed of the motor means, and a signal comparing stage having first input means connected with the monitoring means and second input means connected with the detector means. The signal comparing stage serves to effect the actuation of the motor means at the first speed in the absence of first and second signals, to compare the first signals with the third signals and to thereby effect the actuation of motor means at the second speed, and to compare the second and third signals and thereby effect a reduction of the second speed to zero speed.Still further, the processing means may comprise a source of reference signals which is interposed between the detector means and the signal comparing stage and serves to transmit to the second input of the signal comparing stage signals corresponding to or being otherwise indicative of the first and second signals.

Each of the aforementioned indicia on the web can include a single marker. The detector means then comprises a first detector which serves to generate first signals on detection of successive markers and a second detector which generates second signals on detection of successive markers on the web. The markers on the web preferably form a row of spaced-apart markers, and the first and second detectors are spaced apart from each other (as considered in the direction of lengthwise movement of the web) so that the first detector generates a first signal before the second detector generates a second signal in response to detection of that marker which has caused the first detector to generate a first signal.

The neighbouring blanks are connected to (normally made integral with) each other along lines extending transversely of the web, and the marker which is associated with the foremost blank of the web (such marker can be applied to the next-following or another blank of the web) is spaced apart from the line between the foremost and the next-following'blanks of the web by a predetermined distance. The severing means defines a cutting plane in which the web is severed during each interval of idleness of the motor means, and the distance between the first detector and the cutting plane corresponds to the aforementioned predetermined distance. The distance between the first and second detectors preferably equals the distance which the web covers during deceleration from the first to the second speed.

The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved apparatus itself, however, both as to its construction and its mode of operation, together with additional features and advantages thereof, will be best understood upon perusal of the following detailed description of certain specific embodiments with reference to the accompanying drawing.

Fig. 1 is a schematic end elevational view of a.

blank forming and processing apparatus which embodies one form of the invention; Fig. 2 is a front elevational view of the apparatus as seen in the direction of arrows from the line Il-Il of Fig. 1 , with certain parts omitted; Fig. 3 shows a detail of the apparatus in a view corresponding to that of Fig. 1; Fig. 4 is a schematic perspective view of the transporting unit in the apparatus of Figs. 1 to 3 and of a control unit serving to regulate the speed of the motor which drives the advancing means of the transporting unit; Fig. 5 is a velocity-time diagram denoting the speed of the web during different stages of transport through a distance corresponding to the length of a blank and during separation of the foremost blank from the remainder of the web; and Fig. 6 ís a schematic perspective view of a portion of the transporting unit and a diagrammatic view of a modified control unit.

Figs. 1 and 2 show a portion of a packing machine of the type known as Compas (manufactured by the present applicant), and more particularly a blank forming and manipulating apparatus which can be used in the packing machine to convert a continuous web or strip 7 of coherent blanks into a series of discrete blanks 31 which are thereupon delivered to the wrapping station of the packing machine for conversion into envelopes of successive soft packs. In the view of Fig. 1, the web 7 advances toward the observer of the drawing, i.e., at right angles to the plane of Fig. 1. Fig. 2 shows the apparatus in a side elevational view as seen from the left-hand side of Fig. 1.

As can be best seen in Fig. 2, the apparatus comprises a transporting unit 1 which moves the web 7 lengthwise along a predetermined path, a severing unit 2 which severs the leader of the web 7 at regular intervals to form a succession of discrete blanks or web sections 31, and a blank removing unit 3 which serves to transport the blanks 31 away from the severing station.

The transporting unit 1 conprises a substantially horizontal plate-like support or platform 4 having an upper side or surface 6 which defines the aforementioned path for the web 7. The unit 1 moves the web 7 lengthwise in the direction which is indicated by the arrow 8.

The web 7 is drawn off a source of supply here shown as a reel or bobbin 107 and is deflected by a guide roll 9 which is an idler roll installed upstream of the platform 4. Still further, the transporting unit 1 comprises a web advancing assembly 11 having a driven upper rotary member or roller 12 and a lower rotary member orcounterroller 13 which is located below the path for the web 7 opposite the roller 12 and urges the web against the periphery of the roller 12. The nip of the rollers 12, 13 is at least substantially coplanar with the upper side 6 of the platform 4. The means for driving the roller 12 comprises a variable-speed d-c motor 16 whose output shaft 14 is directly connected with and transmits torque to the roller 12.The web advancing assembly 11 is installed in the region of a hold-down device 17 and upstream of an elongated rail 18 serving to maintain the web 7 in contact with or close to the upper side 6 of the platform 4. The distance between the undersides of the hold-down device 1 7 and rail 18 on the one hand, and the upper side 6 on the other hand, is negligible, i.e., it is only slightly greater than the thickness of the web 7. The hold-down device 17 is a substantially L-shaped member whose upwardly extending leg is affixed to a bridge 19 which, in turn, is affixed to the frame 21 of the blank forming and manipulating apparatus. The frame 21 may form part of or may constitute a constituent of the housing of the packing machine. The horizontal lower leg of the holddown device 17 extends to both sides (i.e., upstream and downstream) of the nip of the rollers 12 and 13.

The transporting unit 1 serves to move the web 7 intermittently and through increments of predetermined length, namely, through distances corresponding exactly to the length of a blank 31.

The leader of the web 7 is thereby advanced into the severing station which extends to the right of a vertical cutting plane defined by the coplanar edges of a pivotable upper knife 23 and a stationary lower knife or counterknife 22 of the severing unit 2 (reference should be had to Fig. 2 of the drawing). The knives 22 and 23 resemble the blades of shears or tongs except that the pivot axis for the upper knife 23 does not or need not intersect the lower knife or counterknife 22. As can be seen in Fig. 1, the upper knife 23 is mounted on a knife holder 24 which is pivotable about the axis of the shaft 26 shown in the lefthand portion of Fig. 1 but omitted in Fig. 2 for the sake of clarity.The pivot axis which is defined by the shaft 26 is parallel to the path for the web 7, and the cutting edges of the knives 22 and 23 extend transversely of such path, i.e., at right angles to the plane of Fig. 2. The shaft 26 receive motion from the main prime mover PM of the packing machine and is driven through the medium of a suitable reversible drive which ensures that the upper knife 23 can turn back and forth in synchronism with the operation of the packing machine.

A roll 27 which is shown in the right-hand portion of Fig. 1 is provided to guide the free end of the movable knife 23 so that the cutting edge of this knife cannot be deflected from the vertical plane including the cutting edge of the counterknife 22. A deflection of the upper knife 23 in the direction of forward movement of the web 7 (arrow 8 in Fig. 2) would prevent the severing unit 2 from making clean cuts across the web, namely, across the lines of contact between neighboring coherent blanks of the web. The roll 27 can be replaced with other suitable means for guiding that end portion of the movable knife 23 which is remote from the holder 24 and shaft 26.

The removing unit 3-f the improved apparatus is located immediately downstream of the severing station including the knives 22 and 23.

The unit 3 comprises a slightly inclined blank supporting plate 29 which slopes downwardly transversely of the direction of transport of the web 7 and has a flat upper side of surface 28. In accordance with a feature of the invention, the upper sides 6 and 28 are located at different levels; in the illustrated embodiment, the upper side 28 of the blank supporting plate 29 is located at a level below the level of the upper side 6 of the platform 4. In order to ensure reliable and rapid transfer of a freshly separated or severed blank 31 from the plane of the upper side 6 into the plane of the upper side 28, the removing unit 3 further comprises displacing means for transferring successive blanks 31 from the severing station onto the upper side 28.The displacing means comprises several elongated parallel strip-shaped towering members 32 which are mounted on a yoke-like carrier 33 which, in turn, is mounted on a supporting element 34 pivotable about the axis of the aforementioned shaft 26 for the knife holder 24. The extent of pivotal movement of the knife 23 and carrier 33 (lowering members 32) about the axis of the shaft 26 is limited by a disk-shaped cam 36 having a circumferentially extending recess 36a for a fixed arresting stud 37 mounted in or on the frame 21.

The length of the recess 36a, as considered in the circumferential direction of the cam 36, determines the angle through which the knife 23 and the carrier 33 can pivot about the axis of the shaft 26, i.e., the parts 23 and 33 are limited to pivotal movements between predetermined first and second end positions. The prime mover PM can pivot the carrier 33 and the knife 23 in synchronism with movements of other mobile components of the packing machine. The arrangement is such that the upper knife 23 pivots downwardly to perform a cutting stroke while the transporting unit 1 is idle, i.e., at a time when the roller 12 is not driven by the motor 1 6.

The plate 29 has two rows 42 and 42' of blank holding means in the form of suction ports 38 which communicate with bores 39 in a frame member or base 41. The bores 39, in turn, communicate with the bore of a coupling device 40 which connects the member 41 with a conduit 140 having a discharge end connected with the intake of'a suction fan 240 or another suitable suction generating device. An adjustable valve 340 in the conduit 140 can be actuated to connect the bores 39 with the suction generating device 240 or with the surrounding atmosphere.

The rows 42 and 42' are parallel with the cutting edges of the knives 22 and 23.

As shown in Fig. 2, the distance between the two rows 42 and 42' of suction ports 38 is selected in such a way that it corresponds substantially to that between two parallel edges of a blank 31 on the upper side 28 of the blank supporting plate 29. This ensures that, when the ports 38 are connected with the suction generating device 240 and the upper side 28 supports a blank 31, such blank is caused to adhere to the plate 29 and is held out of the path of forward movement of the leader of the remaining portion of the web 7. As mentioned above, and as can be seen in Fig. 1, the upper side 28 of the plate 29 slopes downwardly and sideways, as considered in the direction of arrow 8.The inclination is such that the undersides of the lowering strips 32 are located in or are immediately adjacent to the upper side 28 when the upper knife 23 completes a severing stroke, i.e., when the end portion 36b of the recess 36a in the cam 36 receives the arresting stud 37.

The foremost blank 31 can be pushed downwardly into the plane of the upper side 28 (i.e., onto the supporting plate 29 even before the severing of such blank is completed, i.e., while the upper knife 23 performs its-severing stroke. The transporting unit 1 is thereupon caused to advance the web 7 through a distance corresponding to the length of a blank 31, and such advancement can begin as soon as the lowering strips 32 return to the upper end positions which are shown in Fig. 1. Thus, the web 7 can be set in motion to advance in the direction of arrow 8 before the freshly severed blank 31 is transported away from the upper side 28 of the plate 29 which forms part of the removing unit 3.The freshly separated blank 31 cannot interfere with forward movement of the web 7 (i.e., with forward movement of the nextfollowing blank which is still integrally connected with the blank therebehind) because it is located in the plane of the upper side 28 which is staggered with reference to the plane of the upper side 6 of the platform 4 along which the web 7 advances in response to rotation of the advancing roller 12.

The freshly severed blank 31 which has been caused to descend onto the upper side 28 (and to adhere to the plate 29 because the suction ports 38 then communicate with the suction generating device 240) is transported away from the removing unit 3 while the leader of the web 7 advances between and beyond the knives 22 and 23 of the severing unit 2. To this end, the removing unit 3 comprises a gripper 43 which is arranged to transfer the freshly formed blank 31 from the supporting plate 29 and transversely of the web 7, i.e., substantially at right angles to the direction of transport of the web 7 under the action of the roller 12. In the illustrated embodiment, each freshly formed blank 31 is removed in a direction to the left, as viewed in Fig.

1.

The details of the gripper 43 and or tne means for moving this gripper are shown in Fig. 3. The gripper 43 comprises a pivotable body portion 44 which can turn back and forth about the axis of a horizontal shaft 46 and carries two parallel suction arms 47 (only the front suction arm 47 can be seen in Fig. 3). The arms 47 are hollow and their outer ends have suction apertures 48 connected with the aforementioned suction generating device 240 or with a discrete suction generating device (not shown) by a coupling 49 and a flexible hose, not shown.

That marginal portion of the plate 29 which is nearest to the gripper 43 is formed with recesses or cutouts 51 which are disposed above the suction apertures 48 when the gripper 43 is moved to its right-hand end position, as viewed in Fig. 3. This enables the suction arms 47 to attract the freshly separated blank 31 from below. The right-hand end position of the suction arm 47 which is shown in Fig. 3 is indicated by broken lines, as at 47', and the blank 31 which is being attracted by such arm in the position shown at 47' is shown by broken lines, as at 31". The suction arms 47 are thereupon pivoted about the axis of the shaft 46 (in a counterclockwise direction, as viewed in Fig. 3) to remove the blank 31 by transporting it from the position 31" and along an arcuate path which is defined by a pair of arcuate guide members 52 and 52'.For example, the blank 31 can be moved from the position 31" (on the upper side 28 of the plate 29) to the position 31' in which the left-hand marginal portion of the blank (as viewed in Fig. 3) extends into the nip of two intermittently or continuously driven rollers or wheels 53 serving to convey the blank 31 to the next processing station, e.g., to a mandrel which is transported in the packing machine and confines a block of properly arrayed cigarettes, cigars, cigarillos or analogous smokers' products, not shown. Reference may be had to commonly owned U.S. Pat. No. 3,956,870 granted May 18, 1976 to Friedel Kruse et al. The conveyor means including the rollers or wheels 53 can be replaced by other types of conveyor means for blanks 31 without departing from the spirit of the invention.When the suction arms 47 have completed the delivery of a freshly formed blank 31 from the position 31" to the position 31', they return to the end positions 47' of Fig. 3 in order to engage and remove the next blank 31.

Fig. 4 illustrates the control unit which regulates the operation of the transporting unit 1 so as to ensure that the web 7 is invariably severed exactly across the line connecting two neighboring blanks 31. The motor 16 drives the upper roller 1 2 of advancing assembly 11 by way of the output shaft 14, and the upper side of the web 7 is urged against the periphery of the roller 12 by the lower roller 13 which is preferably an idler roller.

The web 7 is provided with indicia in the form of discrete imprinted markers 54, one for each of the blanks 31 (only one of these markers is shown in Fig. 4). The positions of the markers 54 with reference to the lines along which the neighboring blanks 31 adhere to each other upstream of the severing unit 2 are selected in such a way that the signals which are generated by means for detecting the markers 54 are transmitted at predetermined stages of movement of the foremost blank 31 of the web 7 toward and through the severing station. The detecting means comprises two discrete detectors 56 and 57 which constitute photoelectric transducers and are located above and in line with the path of movement of successive markers 54 toward the severing unit 2.The outputs of the transducers 56 and 57 are connected with the corresponding inputs of a source 58 of reference signals which has a third input connected with a pulse generator 1 63 by a conductor 63. The pulse generator 163 transmits signals in rhythm with operation of the packing machine, i.e., in synchronism with movements of various mobile components of such machine. This pulse generator is driven by the prime mover PM and can comprise a disc having one or more magnets travelling past a proximity detector switch which generates a signal or pulse whenever a magnet advances therealong.

The output of the source 58 of reference signal is connected with one input of a signal comparing stage 59 another input of which is connected with a tachometer generator 61. The latter monitors the speed of the motor 16 and transmits signals denoting the speed of the shaft 14, i.e., the speed of the driven roller 12. The signal comparing stage 59 has outputs which are connected with the controls 11 6 for the motor 1 6 by conductor means 62. The signals which are transmitted by the conductor means 62 can effect acceleration, deceleration or stoppage of the motor 16, i.e., acceleration, deceleration or stoppage of the roller 12 and web 7.

The distance between the front transducer 57 and the cutting or severing plane, as considered in the direction (arrow 8) of lengthwise movement of the web 7, corresponds to the distance between a marker 54 and the line of connection of the corresponding blank 31 with the nextfollowing blank. The distance between the front and rear transducers 57 and 56, again as considered in the direction of lengthwise movement of the web 7, is selected in such a way that it is in a predetermined relationship with the ratio of the two speeds of the motor 1 6 when the web is in motion, i.e., with the difference between the higher speed at which the web 7 is driven immediately upon completion of a severing operation and the lower speed at which the web is driven during the interval preceding full stoppage of the web preparatory to movement of the knife 23 from its upper to its lower end position (to thereby sever the web across the line connecting the foremost blank 31 with the immediately following blank). The distance between the transducers 56, 57 exceeds or equals the distance which the web 7 covers during deceleration from the higher first speed to the lower second speed.Such spacing between the transducers 56 and 57 ensures that the web 7 invariably advances at the reduced second speed when the motor 1 6 receives a "stop" or "arrest" signal, i.e., when the roller 12 is to be brought to a complete halt preparatory to separation of the foremost blank 31 from the remainder of the web 7.Furthermore, such spacing between the tranducers 56 and 57 ensures that the web 7 is advanced at the reduced second speed when a marker 54 moves into register with the front transducer 57 which effects stoppage of the motor 1 6 via signal processing means including the source 58 of reference signals, signal comparing stage 59, conductor means 62 and controls 11 6. An advantage of the feature that stoppage of the web 7 (i.e., the generation of a "stop" or "arrest" signal for the motor 16) is effected after the web 7 has been decelerated to the lower of two speeds is that this renders it much more likely that the advancing unit 1 will arrest the web 7 at the very instant when a line at the locus of connection of the foremost unseparated blank 31 with the next-following blank is in exact register with the cutting plane, namely, with the vertical plane including the cutting edges of the knives 22 and 23.

The source 58 of reference signals can comprise a logic circuit and a function generator of the type shown at 77 and 78 is Fig. 4 of commonly owned U.S. Pat. No. 4,059,940 granted November 1977 to Menge et al. Such circuits are manufactured by the firm Hauser, Oberschopfheim, Federal Republic Germany, and are known as POS E2GN. The arrangement is such that the logic circuit causes the function generator to transmit a signal until the logic circuit receives a different signal. Thus, the function generator transmits a given signal while the logic circuit receives a signal via conductor means 63; such signal is replaced with a different signal when the logic circuit receives a signal from the detector 56; and a further signal appears at the output of the function generator when the logic circuit receives a signal from the detector 57.

The signal comparing stage 59 is of conventional design.

The operation of the apparatus which is shown in Figs. 1 to 4 is as follows: As already mentioned above, the transporting unit 1 is designed to advance the web 7 in stepwise fashion. In Fig. 5, the velocity n of the web 7 (i.e., the RPM of the output shaft 14 and roller 12: is measured along the ordinate, and the time t is measured along the abscissa. A cycle is completed during the interval between the instants to and t,. The motor 1 6 is idle during the interval between the instants to and t, (i.e., the velocity n of the web 7 is then zero).The conductor 63 transmits a pulse from the pulse generator 1 63 at the instant t1 whereby the roller 12 is rapidly accelerated from zero speed to the maximum or first speed n, (such acceleration is completed during the interval between t, and t2), i.e., the web 7 is transported lengthwise (arrow 8) at the first speed n, shortly after the uppermost input of the source 58 of reference signals shown in Fig. 4 receives a signal from the pulse generator 163. The web 7 continues to advance at such maximum or first speed n, until the major part of the foremost unseparated blank 31 advances beyond the cutting plane, i.e., beyond the cutting edges of the knives 22 and 23.This means that the major part of the foremost unseparated blank 31 is advanced beyond the knives 22, 23 and into the removing unit 3 (i.e., into the space above the upper side 28 of the blank supporting plate 29 (before the speed of the motor 1 6 is reduced. Such reduction is caused by the rear transducer 56 in response to detection of the oncoming marker 54. The (first) signal which the transducer 56 transmits to the median input of the source 58 of reference signals causes the source 58 to transmit a signal which is applied to the motor controls 11 6 via signal comparing stage 59 and conductor means 62 so that the speed of the roller 1 2 is rapidly reduced from n, to the lower or second speed n2 which can be and preferably is only a small fraction of the speed n,.

The interval between the instants t2 and t3 is that period during which the web 7 is advanced at the first speed n1, and the interval between the instants t3 and t4 elapses during deceleration of the web 7 from the first speed n, to the second speed n2. The stage 59 compares the signal which is transmitted by the source 58 in response to detection of the oncoming marker 54 by the transducer 56 with the signal which is transmitted by the tachometer generator 61 and then furnishes a signal or a set of signals which initiate the reduction of speed from n, to n2 within the interval which elapses between the instants t3 and t4. The speed of the web 7 is reduced from n, to n2 before the marker 54 which has induced the transducer 56 to transmit the just discussed signal to the median input of the source 58 reaches the transducer 57.Thus, the web 7 is advanced at the lower or second speed n2 during a certain stage of its lengthwise movement through a distance corresponding to the length of a blank 31, namely, during the interval between t4 and5, as viewed in Fig. 5. The marker 54 then reaches the transducer 57 which transmits to the lowermost input of the source 58 a (second) signal serving to initiate complete stoppage of the motor 1 6. Such stoppage takes place after a relatively short interval of time (between t5 and t6 as seen in Fig. 5) which can be calculated and maintained with a high degree of accuracy because the second speed n2 need not be high, i.e., the web 7 can be reliably arrested in a position in which the line between the foremost blank and the next-following blank 31 of the web 7 is located in exact register with the cutting edges of the knives 22 and 23. The web 7 is thereupon maintained at the speed n=O for an interval which elapses between the instants t, and t, and which is sufficiently long to allow for completion of the severing operation and for return movement of the knife 23 and lowering strips 32 to the upper end positions shown in Fig.

1.

As explained in connection with Figs. 1 and 2, the lowering strips 32 share the pivotal movements of the upper knife 23 and cause the foremost blank 31 of the web 7 to move into the plane of the upper side 28 of the plate 29 in the course of the severing operation, i.e., while such blank 31 is in the process of being separated from the nextfollowing blank of the web 7. The lowered foremost blank 31 is attracted by the plate 29 because the suction ports 38 in this plate then communicate with the intake of the suction generating device 240. The connection between the ports 38 and the device 240 remains intact until the suction arms 47 assume the positions 47', i.e., until the free end portions of the suction arms 47 enter the cutouts 51 of the plate 29 so that the apertures 48 (which then communicate with the corresponding suction generating device) ensure that the freshly separated blank 31 is compelled to share the movement of the suction arms 47 from the positions 47' to the solid-line positions of Fig. 3. The valve 340 connects the suction ports 38 to the atmosphere when the arms 47 assume the positions 47' so that these ports do not interfere with movement of the freshly separated blank 31 from the position 31" to the position 31' of Fig. 3.The guides 52 and 52' ensure that the blank 31 remains in a predetermined arcuate path during travel from the position 31", to the position 31', i.e., that the lefthand edge or marginal portion of such blank enters the nip of the wheels 53 which convey the blank to the next processing station, such as the aforediscussed wrapping station where the blank is draped around a mandrel and around the block or properly arrayed cigarettes in such mandrel.

The gripper 43 is thereupon immediately returned to its normal position in which the arms 47 assume the broken-line positions 47' of Fig. 3 and are ready to attract and remove the next blank 31 (which then occupies the position 31" of Fig. 3).

The web 7 can be advanced while the arms 47 transport a freshly separated blank 31 from the plane of the upper side 28 of the plate 29 because this plane is located at a level below that of the upper side 6 of the platform 4. Thus, all that is necessary is to maintain the web 7 at a standstill during severing by the cutting edges of the knives 22, 23 and during the immediately following rapid retraction of the knife 23 and lowering or displacing strips 32 to the upper end positions of Fig. 1. As mentioned above, the freshly separated blank 31 is attracted by the suction ports 38 as soon as it reaches the plane of the upper side 28 of the plate 29 so that such blank cannot interfere with forward movement of the next blank 31 into the space behind the cutting plane, i.e., into the space above the plate 29.

Fig. 6 shows a portion of a modified control unit wherein the motor 16 for the roller 12 of the advancing assembly 11 receives signals from a signal comparing stage 59 one input of which is connected with the tachometer generator 61 and the other input of which is connected with the output of a modified source 71 of reference signals. The latter has two inputs one of which is connected with the pulse generator (not shown) by way of conductor means 63 and the other of which is connected with the output of a single detector 70 (e.g., a photoelectric transducer which scans the web 69 for the presence or absence of indicia. The web 69 has a composite indicium consisting of two aligned markers (72, 73) for each of its blanks, and such markers may constitute printed dark spots which form a row or file along one marginal portion of the web 69.The distance between the cutting edge of the stationary counterknife 22 (not shown in Fig. 6) and the detector 70 equals the distance between the rear marker 72 and the line connecting the foremost blank of the web 69 with the nextfollowing blank. The distance between the markers 72 and 73 is proportional to the difference between the higher speed n, and the lower speed n2 of the web 69; such distance equals or exceeds the distance which the web 69 covers during deceleration from the speed n, to the speed n2. The web 69 is accelerated from zero speed to the higher speed n, in response to transmission of a signal from the pulse generator, via conductor means 63 and to the corresponding input of the source 71 of reference signals.The (first) signal which the transducer 70 transmits to the corresponding input of the source 71 on detection of the markers 72 effects a reduction of the speed of the web 69 from n, to n2, and the (second) signal which the transducer 70 transmits to the source 71 on detection of the marker 73 effects a reduction of the speed n, to zero speed.

The controls 11 6 are commercially available components whose exact construction forms no part of the present invention. For example, such controls may comprise or constitute a conventional amplifier circuit.

It goes without saying that the indicia 54 and 72-73 can be replaced by other types of indicia which need not be imprinted onto the web 7 or 69, e.g., by indicia in the form of perforations, notches or combinations of several different indicia (e.g., a marker in the form of a perforation which replaces the marker 72 and a marker in the form of a notch which replaces the marker 73 of Fig. 6). The nature and mode of application of indicia depend on the selected detector means and on the nature of signals which are to be transmitted to the selected source of reference signals.

It has been found that the improved apparatus allows for the making and processing of a larger number of blanks per unit of time than any heretofore known apparatus. This is attributable to the fact that the web 7 or 69 can be caused to advance (at the higher first speed n,) while the freshly separated blank 31 is still located in the removing unit 3, i.e., on the upper side 28 of the plate 29. The plane of the upper side 28 is not identical with that of the upper side 6, i.e., the freshly separated blank 31 cannot interfere with forward movement of the leader of the remaining portion of the web 7, even though such freshly separated blank is still located in the removing unit 3.

Another important advantage of the improved apparatus is that the web 7 or 69 can be arrested in accurately determined positions, i.e., always when the line between two neighbouring blanks is in exact alignment with the cutting edges of the knives 22 and 23. Therefore, the dimensions of all blanks 31 are the same and each of these blanks carries the entire image which is to be seen at the outer side of the respective pack. Furthermore, the advancing, severing and removing units 1,2 and 3 are very simple and compact so that the improved apparatus occupies a surprisingly small amount of space in a packing machine for cigarettes or the like. The control means for the motor 1 6 are simple and reliable so that the apparatus requires a minimum of maintenance and a minimum of supervision in actual use of the packing machine.

A further important advantage of the improved apparatus is that the web and the blanks are treated gently, i.e., there is no need to employ entraining elements in the form of pawls whose pallets or like elements must penetrate into marginal notches or perforations of the web in order to entrain the web during the last stage of forward movement to a position in which a line between two neighboring blanks is in exact alignment with the cutting edge of the stationary knife. This also contributes to a higher output of the apparatus because the number of rejects is negligible or zero and the packing machine is less likely to turn out defective packs which require segregation from packs having satisfactory envelopes.

Claims

1. In a packing machine, particularly in a machine for confining blocks of cigarettes or analogous smokers' products in soft packs, apparatus for converting a web consisting of a series of coherent blanks of identical length into discrete blanks, comprising means for intermittently transporting a web which has an indicium for each of its blanks lengthwise along a predetermined path, including variable-speed motor means and means for advancing the web along said path in response to actuation of said motor means; severing means adjacent to a predetermined portion of said path and operable to separate successive foremost blanks from the web while said motor means is idle; means for removing successive separated blanks from said path; and control means for said motor means, including means for initiating the actuation of said motor means at a first speed upon completion of a severing operation, detector means arranged to scan the web for the presence of said indicia and to generate a first and thereupon a second signal on detection of the indicium denoting the foremost blank of the web, and means for processing said signals and for transmitting the processed signals to said motor means so that the first signal effects a deceleration of said motor means from said first to a lower second speed before and the second signal effects a deceleration of said motor means from said second speed to zero when said advancing means completes the transport of the web through a distance equal to the length of a blank.

2. The apparatus of claim 1, wherein said advancing means comprises a first rotary member disposed at one side of said path and receiving torque from said motor means and a second rotary member disposed at the other side of said path opposite said first rotary member and arranged to urge the web against said first rotary member.

3. The apparatus of claim 1, wherein said processing means includes means for monitoring the speed of said motor means and for generating third signals whose characteristics are indicative of the speed of said motor means and a signal comparing stage having a first input receiving signals from said monitoring means and a second input receiving signals from said detector means, said stage being arranged to effect the actuation of said motor means at said first speed in the absence of said first and second signals, to compare said first signals with said third signals and to thereby effect the actuation of said motor means at said second speed, and to compare said second and third signals to thereby effect a reduction of said second speed to zero speed.

4. The apparatus of claim 3, wherein said processing means further comprises a source of reference signals interposed between said detector means and said stage and arranged to transmit signals indicative of said first and second signals to the second input of said stage.

5. The apparatus of claim 1 for converting a web wherein each indicium has a single marker into a succession of discrete blanks, wherein said detector means comprises a first detector arranged to generate said first signals on detection of successive markers and a second detector arranged to generate said second signals on detection of successive markers.

6. The apparatus of claim 5, wherein said markers of the web form a row of spaced-apart markers and said first and second detectors are spaced apart from each other, as considered in the direction of lengthwise movement of the web, so that said first detector generates a first signal before said second detector generates a second signal in response to detection of that marker which has caused said first detector to generate a first signal.

7. The apparatus of claim 6, wherein the neighboring blanks of the web are connected to each other along lines extending transversely of the web and the marker which is associated with the foremost blank of the web is spaced apart from the line between the foremost blank and the next-following blank of the web by a predetermined distance, said severing means defining a cutting plane in which the web is severed during each interval of idleness of said motor means and said first detector being spaced apart from said plane by a distance corresponding to said predetermined distance.

8. The apparatus of claim 7, wherein the distance between said first and second detectors at least equals that distance which the web covers during deceleration from said first speed to said second speed.

9. The apparatus of claim 1 for converting a web wherein each indicium has two markers for each of its blanks into a succession of discrete blanks and wherein the markers form a row extending in the longitudinal direction of the web, wherein said detector means comprises a single detector which is arranged to generate a first signal on detection of one marker of an indicium and to generate a second signal on detection of the other marker of the same indicium.

10. The apparatus of claim 9, wherein the neighboring blanks of the web are connected to each other along lines extending transversely of the web and the severing means defines a cutting plane in which the web is severed during each interval of idleness of said motor means and which is spaced apart from said detector, the other marker of the indicium which is associated with the foremost blank of the web being spaced apart from the line between the foremost blank and the next-following blank of the web by a distance which at least approximates the distance between said detector and said cutting plane and the markers of each indicium being spaced apart from each other, as considered in the longitudinal direction of the web, the distance between the markers of each indicium being proportional to that distance which the web covers during deceleration from said first speed to said second speed.

11. The apparatus of claim 10, wherein the distance between the two markers of an indicium on said web at least equals the distance which the web covers during deceleration from said first to said second speeds.

12. The apparatus of claim 1, wherein said detector means comprises at least one photoelectric transducer.

13. The apparatus of claim 1, wherein said motor means comprises a d-c motor.

14. The apparatus of claim 1, wherein said processing means further comprises means for monitoring the speed of said motor means, said monitoring means comprising tachometer generator means.

1 5. The apparatus of claim 1, wherein each of said indicia comprises at least one marker which is imprinted onto the web.

16. The apparatus of claim 1, wherein said path is located in a first plane and said removing means includes means for supporting successive separated blanks in a second plane, said first and second planes being offset with reference to each other.

17. The apparatus of claim 16, wherein said first and second planes are disposed at different levels.

1 8. The apparatus of claim 16, wherein said removing means further comprises displacing means operable to move successive separated blanks from said first plane into said second plane.

19. The apparatus of claim 18, further comprising means for operating said displacing means while said motor means is idle.

20. The apparatus of claim 18, wherein said second plane is located at a level below said first plane and said displacing means comprises means for lowering successive separated blanks from said first plane into said second plane.

21. The apparatus of claim 20, wherein said lowering means includes means for pushing the foremost blank of the web into said second plane during the interval of idleness of said motor means.

22. The apparatus of claim 16, wherein said supporting means includes means for holding the foremost blank of the web in said second plane, and further comprising means for transferring freshly separated blanks from said second plane.

23. The apparatus of claim 22, wherein said transferring means includes means for engaging and moving a freshly separated blank and said holding means is arranged to release such blank at the time the blank is engaged by said transferring means.

24. The apparatus of claim 23, wherein said holding means comprises a suction-operated device.

25. The apparatus of claim 23, wherein said holding means includes a plurality of suction ports in said supporting means, suction generating means, and means for selectively connecting said ports with said suction generating means.

26. The apparatus of claim 25, wherein each blank of the web has two edge portions parallel to and located opposite each other, said suction ports being arranged in two rows each adjacent to a different edge portion of the freshly separated blank in said second plane.

27. The apparatus of claim 23, wherein said transferring means comprises means for moving a freshly separated blank from said second plane in a direction substantially at right angles to the direction of lengthwise movement of the web.

28. The apparatus of claim 16, wherein said removing means further comprises displacing means operable to move the foremost blank of the web from said first into said second plane during the interval of idleness of said motor means, said severing means comprising a mobile knife and means for moving said knife transversely of said path, said knife moving means being arranged to operate said displacing means.

29. The apparatus of claim 1, wherein said removing means includes means for transferring successive separated blanks from the region of said severing means along an arcuate second path and in a direction substantially at right angles to the direction of lengthwise movement of the web along said first mentioned path.

30. In a packing machine, particularly in a machine for confining blocks of cigarettes or analogous smokers' products in soft packs, apparatus for converting a web consisting of a series of coherent blanks of identical length into discrete blanks, substantially as herein described with reference to and as illustrated in the accompanying drawings.