GB2285414A

GB2285414A - Making embossed blanks of flexible sheet material

Info

Publication number: GB2285414A
Application number: GB9425316A
Authority: GB
Inventors: Gottfried Hoffmann; Josef Glosmann
Original assignee: Topack Verpackungstechnik GmbH
Current assignee: Topack Verpackungstechnik GmbH
Priority date: 1993-12-15
Filing date: 1994-12-15
Publication date: 1995-07-12
Also published as: DE4342737A1; ITMI942242A0; IT1271058B; GB9425316D0; ITMI942242A1; JPH07256347A

Description

2285414 METHOD OF AND APPARATUS FOR MAKING EMBOSSED BLANKS OF FLEXIBLE

SHEET MATERIAL The invention relates to improvements in methods of and in apparatus for treating running webs of deformab sheet material, and more particularly to improvements in methods of and in apparatus for treating webs which consist of successions of coherent blanks, e.q., hlank,s which can be converted into envelopes for arrays of rod-shaped articles in packets of plain or filter cigare-:-Z:eS or the like. Still more particularly, the invention relates to improvements in methods of and in apparatus for impressing designs into successive blanks of a seriess of coherent successive blanks which are to be separated from each other upon completion of the impressing operation.

It is known to impress suitable designs (e.g., in the form of numerals and/or letters) into successive blanks of a web which consists of a series of coherent blanks and is made of or contains a metallic foil. A drawback of heretofore known methods and apparatus is that they do not contemplate and do not permit rapid and convenient conversion from the imprinting of relative-y long blanks to the imprinting of relatively short blanks or vice versa. As a rule, the apparatus for the practice of heretofore known methods utilize a nair of emboSsina rolls which are driven at a constant speed and de_"_:.-_ a nip for a web which is advanced at the peripherai i e z speed of the embossing rolls. The peripheral surfaces of the embossing rolls are driven in opposite directions so that successive increments of both peripheral surfaces advance in the direction of advancement of the web when such increments approach and move past the nip of the two embossing rolls. The web, e.g., a strip of aluminum f -oil, is advanced through the nip of the embossing rolls and is provided with longitudinally spaced apart designs the nature and/or the dimensions of which depend upon t re of' the pattern which is being impressed by L-he natuthe embossing rolls. one of the embossing rolls is normally driven and the other embossing roll is caused to rotate as a result of engagement with the respective;ide oil the running web.

A drawback of such methods and apparatus is that it is necess-ary to interrupt the impressing operation a onz -n-erval of time if the operator or operators L of the appara-tus wish to switch from the imprinting of a web consisting of relatively long coherent blanks to to imor.4--ing oil a web consisting of relatively short coherent blanks or the other wav around. Furthermore, it is necessary to maintain a supply of spare embossing rolls and a supply of spare advancing means for the webs.

3 one feature of the present invention resides in the provision of a method of treating a web of deformable sheet material which consists of a succession of coherent blanks. The method comprises the steps of advancing -he web longitudinally in a predetermined direction along a predetermined path, and impressing a design only into preselected portions of successive coherent blanks during advancement of such sections of successive blanks along a predetermined portion of the path.

In accordance with a presently preferred embodiment, the method further comprises the steps of separating successive impressed blanks from a leader of the web downstream of the predetermined portion of the path (as seen in the predetermined direction), and converting L.he separated impressed blanks into envelopes or wrappers for arrays of rod-shaped articles, particularly into inner envelopes for arrays of (e.g., twenty) cigarettes (in quincunx formation) in hard or soft cigarette packets.

Each blank of the running web includes first and second end portions which are spaced apart from eacn. other in the predetermined direction, and an intermediate portion between the two end portions. Such blanks are preferably provided with designs in such a way that the preselected section of each blank includes at least 4_ one end portion of the respective blank, i.e., at least the intermediate portion of each blank is not provided with a design. The impressing step of such method can comprise advancing the web through a nip between the peripheral surfaces of two embossing rolls in the predetermined portion of the path, and driving the rolls az an at least substantially constant speed in a direction such that successive increments of the peripheral surfaces approaching and moving along the nip advance in the predetermined direction during movement along the nip. The web advancing step of such method can include transporting the web in the predetermined direction at a speed which at least approximates the at least substantially constant speed during advancement of the preselected sections of successive blanks along the predetermined portion of the path. The web advancing step can further comprise =ansporting the web at at least one second speed, which is different from the at least substantially constant speed, during advancement of preselected sections of successive coherent blanks of the web toward the predetermined portion of the path, i.e., while the intermediate Dortions of successive blanks are caused to advance through the nip of the embossing rolls. The at least one second speed can exceed the at least substantially constant speed.

The advancing step preferably includes pulling the web in the predetermined direction at a second portion of the path downstream of the predetermined portion (as seen in the predetermined direction). Such pulling step can comprise engaging the web by the peripheral surfaces of two rotary advancing rolls which are disposed at opposite sides of the second portion of the path and moving the peripheral surfaces of the advancing rolls at the at least substantially constant speed during advancement of preselected sections of successive blanks along the predetermined portion of the path as well as at at least one second speed during advancement of preselected sections of successive blanks toward the predetermined portion of the path. The moving step can include driving at least one of the advancing rolls bv at least one variable- speed motor, e.g., an electric motor. Such method can further comprise the step of regulating the peripheral speed of the advancing rolls as a function of at least one variable parameter of a web processing machine (such as a packing machine for plain or filter cigarettes) receiving successive blanks in a third portion of the path downstream of the second portion (as seen in the predetermined direction). he method can further comprise the step of selecting the at least substantially constant speed of the peripheral (0 surfaces of the embossing rolls as a function of at least one variable parameter of the processing machine, particularly in dependency upon the rate of processing successive impressed or embossed and separated blanks by the machine.

An important feature cf the improved method is that it renders it possible to select (vary) the length of successive blanks which are to be separated from the leader of the web downstream of the second portion of the path (as seen in the predetermined direction). The step of varying includes advancing the web at a first- speed during advancement of preselected sections of successive blanks along the predetermined portion of the path and advancing the web at at least --ne different second speed during advancement of preselected sections of successive blanks toward the predetermined portion of the path so that each blank which advances beyond the predetermined portion of the path includes an impressed section of fixed length and a second section having a length depending upon the second speed. Such method can further comprise the steps of generating signals which denote different second speeds and utilizing selected second signals to determine the second speed of the web during advancement of preselected sections of successive blanks toward the predetermined portion of the path.

1 Another feature of the invention resides in the provision of an apparatus for treating a web of deformable sheet material which consists of a succession of coherent blanks. The apparatus comprises means for advancing the web longitudinally in a predetermined direction a!-ong a pred eetermined path, and means for impressinC each blank a design only into a preselected section o4L of the succession of coherent blanks. The impressing means comprises cooperating first and second embossing rolls having peripheral surfaces and disposed at opposite sides of a nredetermined portion of the path, and means for driving the first embossing roll at a substantially constant speed in a direction such that successive increments of the peripheral surfaces move in the predetermined direction during movement along the predetermined portion of the path.

At least one predetermined portion of the peripheral surface of one of the embossing rolls has a pattern which impresses the design into the preselected sections of successive blanks during advancement of the preselected sections of successive blanks along the predetermined portion of the path. The peripheral surface of the one embossing roll is further provided with a recess which alternates with the pattern, as seen in the circumferent-al direction of' the one embossing roll, durina advancement ip of the pattern and the recess along the predetermined portion of the path.

Each blank which forms part of the web includes first and second end Dortions which are spaced apart from each other in the mredetermined direction and an intermediate portion between the respective end por---Jcs. In accordance with an advantageous feature of the invention, each preselected section of a blank includes at least one end portion of the respective blank but not the intermediate portion. In other words, the embossing rolls cooperate to amply designs to successive coherent blanks in such a way that each design is applied to at least one end portion but not to the intermediate portion of a blank advancing through or along the predetermined portion of the path.

The advancing means preferably includes means for Dulling the web in a second portion of the path downstream of the predetermined portion (as seen in the predetermined direction). The means for pulling the web can include two advancing rolls having peripheral surfaces defining for the web a nip at the second portion of the path, and means for driving the peripheral surfaces of the advancing rolls at a first speed at least approximatinj the at least substantially constant speed and at least one different second speed. The means for dr-i7ing zhe Cl advancing rolls can include a function generator which is-actuatable to raise the speed of the peripheral surfaces of the advancing rolls from the first speed to a higher second speed at preselected intervals and ffor preselected periods of time.

The apparatus can further comprise means for regulating the peripheral speed of the aforementioned first embossing roll as a function of the speed of advancement of the web along a further portion of the path downstream of the predetermined portion (as seen in the predetermined direction).

Still further, the apparatus can comprise at 4 the web immmediate least one magazine for a looped portion o. or closely upstream of the predetermined portion of the path.

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 presently preferred specific embodiments with reference to the accompanying drawings.

FIG. 1 is a schematic elevational view of an apparatus which embodies one form of the invention and of a portion of a machine which receives impressed blanks C from. the apparatus; FIG. 2 is an enlarged transverse sec--ional of two embossing rolls which are utilized in the apparatus of FIG. 1; FIG. 3 is a plan view of the embossing rolls which are shown in FIG. 2; FIG. 4 is a fragmentary plan view of a portion of a web consisting of relatively long coherent blanks each of which is provided with an imprinted first and second end portion; and FIG. 5 is a similar fragmentary plan view of a portion of a web consisting of relatively short coherent blanks.

1% FIG. 1 shows an apparatus which embodies one form of the present invention and serves to deliver a succession of discrete blanks30 to a converting machine 46, e.g., a cigarette packing machine having means for converting successive discrete imprinted blanks 30 into inner envelopes for arrays 44 of rod-shaped articles (e.g., plain or filter cigarettes). The apparatus includes means 14 for advancing a web 1 of deformable sheet material (e.g., a strip of aluminum foil or a laminated strip including a layer or film of metallic material and a layer of paper or the like) from a suitable source (e.g., a bobbin, not shown) along a predetermined path and in a predetermined direction (downwardly as seen in FIG. 1). The advancing means 14 includes two rolls which define a nip for the web 1 and one of which is driven at a variable speed by a suitable prime mover, such as an electric motor 27. The apparatus preferably further includes second advancing means 3 disposed between the source and the advancing means 14 and including a second pair of advancing rolls one of which is driven by a variable-speed prime mover 2, e.g., an electric motor. The rolls of the second advancing means 3 also define a nip for the running web 1. The purpose of the advancing means 3 is to move the web 1 at a rate 12- such that the web includes at least one looped portion in a magazine 4 located immediately upstream oil or at least relatively close to a predetermined portion of the path for the web 1, namely a portion accommodating a unit 16 which serves to impress a design into presele=ed sections of successive coherent blanks 30a or 30b (see FIGS. 4 and 5) which together constitute the web 1. The magazine 4 can be designed in any well known manner, e.g., it can comprise pneumatic means for looping the running web 1 between the nip of the rolls forming part of the further advancing means 3 and the nip of two embossing or impressing rolls 17, 18 forming part of the unit 16.

The size of the loop or loops in the magazine 4 is monitored by a battery of photoelectronic (or other suitable) detectors 6 which transmit signals denoting the monitored size of the illustrated loop in the magazine 4 to an amplifier 7 in'the circUit of the electric motor 2 for one roll of the further advancing means 3. The purpose of the amplifier 7 is to regulate the speed of the motor 2 in such a way that the size of the loop in the magazine 4 remains at least substantially cons-al-z. The amplifier 7 includes inputs Nhitz:h are connected to the outputs of the detectors 6, a -Fur--:i.-er input connected to the output of a conventional dev-J---- 8 a tachomete-r 13 generator) which transmits signals denoting the momentary speed of the motor 2, and an additional input for signals from a pulse generator 9. The latter receives signals from a prime mover 11 (e.g., a variable-speed electric motor) which serves to drive an endless belt conveyor 12 forming part of the processing machine 46. The motor 11 for the conveyor 12 receives control potential from a variable or adjustable potentiometer 13 receiving signals from the pulse generator 9 and forming part of a secondary circuit serving to regulate the speed of the motor 11 and conveyor 12. The pulses which the generator 9 transmits to the amplifier 13 for the motor 11 are indicative of the speed of the processing (packing) machine 46, i.e., of the rate at which the machine 46 can process blanks 30 which are separated from the leader of the web 1 downstream of the advancing means 14. Thus, the speed at which the motor 11 drives the conveyor 12 is a function of the momentary speed of the processing machine 46, namely of the rate at which the machine 46 processes separated blanks 30 per unit of time.

The advancing means 14 is designed to pull the web 1 from the magazine 4 through the nip of the embossinq rolls 17 and 18. The presently preferred configuration of the peripheral surfaces of the embossing rolls 17 an18 is illustrated in FIGS. 2 and 3.

1 it As can be seen in FIG. 2, the embossing roll 18 of the impressing unit 16 is biased toward L-he Peri;,-heral surface of the complementary roll 17 by resilient --neans (FIG. 2 shows a coil spring 21) and is driven at an at least substantially constant speed by an electric motor 19. The entire peripheral surface of the rol' 18 is provided w--,-h a;Dattern which cooperates wit.a complementary pattern 22 in a preselected section of the peripheral su-r.AEace of the roll 17. The two mentary patterns ensure that the roll 17 is driven the speed of the roll' 18 when the motor 19 is on, successive increments of the peripheral surfaces of the rolls 17, 18 advance in the direction of advancement of the web 1 through the nip of the rolls 17, 18 when the motor 19 is on to drive the roll 18. The patterns at the peripheral surfaces of the rolls 17, 18 coopera-ze with the biasing means 21 to ensure that these rolls are form- and forcelockingly coupled to each other.

FIG. 3 shows that the pattern of the roll 18 covers its entire peripheral surface. On the other hand, the pattern 22 of the roll 17 extends along an -=r,: of selected magnitude (FIG. 2 shows an arc of appro 120') and the median Dortion of such Pattern with a recess 23 which is r)--o-.rided in the surface of the roll 17 and extends along an are o-;:

Is proximately 24C. The pattern 22 and the recess 23 alternately advance toward and through and beyond the nip of the embossing rolls 17, 18 when the motor 19 is on to drive these rolls at an at least substantially constant speed so that the roll 15 is rotated in a counterclockwise direc+ --;--n and the roll 17 is rotated -1- a clockwise direction, as viewed in FIG. 2.

The pattern 22 further includes two relatively narrow strip-shaped arcuate portions adjacent the two end -faces of the roll 17 and cooperating with the complementary portions of the pattern covering the entire peripheral surface of the roll 18; this ensures that the aforementioned force- and form-locking connection between the rolls 17, 18 remains intact even when the recess 23 is in the process of advancing along the nip of --he rolls 17 and 18.

preselected section of each of a succession of coherent blanks 30a or 30b is provided with a design during advancement of such preselected section along the nip of the rolls 17, 18 at a time when the profile 22 of the roll 17 advances along the nip. The remaining second section of each blank 30a or 30b is not provided with a desizn because such second section advances through the np of the rolls 17, 18 while the recess 23 is adjacent the res3ective side of the runninc web 1.

16 The rotational speed of the motor 19 for the roll 18 is controlled by an adjustable amplifier 24 which receives signals denoting at least one parameter of the processing machine 46 from the pulse generator 9. A secondary circuit for the motor 19 contains a signal transmitting RPM indicator 26.

The motor 27 which drives one roll of the web advancing means 14 is in circuit with an adjustable amplifier 28 receiving signals from the pulse generator 9 as well as from a signal generating indicator 29 o--" the Eurther receives RPM of the motor 27. The amplifier 28.1 t signals from a function generator 31 which cooperates with the amplifier 28 to select one of two or more different speeds for the rolls of the web advancing means 14. The speed of the rolls forming part of suchweb ad-7a.nc-ing means is or can be varied while the recess 23 of the embossing roll 17 advances along the adjacent side of the running web 1, i.e., during intervals between successive embossing or impressing operations.

The illustrated function generator 31 memorizes functions (shown schematically at 31a, 31b, 31c... 31n) each of which is indicative of a di-f-Perent second of the rolls forming part of the web advancing means 14. As will be explained hereinafter, the apparatus can convert the web 1 into a succession of' coherent blanks each having any one of n different lengths, depending upon the nature of signals from the function generator 31 to the amplifier 28. The motor 27 is driven in such a way that the rolls of the advancing means 14 pull the web 1 from the magazine 4 at the exact (at least substantial-y constant) peripheral speed of the embossing rolls 17, 18 while the pattern 22 of the roll 17 cooperates with the adjacent portion of the pattern covering the entire peripheral surface of the roll 18 to impress a design into selected portions of successive blanks (such as 30a or 30b) which together constitute the running web 1. The width of the web 1 does not exceed the width of the recess 23 (as seen in the axial direction of the embossing roll 17).

The amplifier 28 embodies or is combined with a computer (not specifically shown) which serves to process signals from the function generator 31 with signals from the pulse generator 9 in such a way that - embossing longitudinally spaced apart the freauency of portions of the running web 1 depends upon the frequency at which the machine 46 can process successive separated and e=ossed blanks 30 per unit of time. Furthermore, the amplifier 28 cooperates with the function generator 31 to determine the s-,)eed of' advancement of the web 1 between ----e ^patterned peripheral surface of the embossing 119 roll 18 and the recess 23 in the peripheral surface of the embossing roll 17. The second speed which is determined by the signal from the function generator 31 to the amplifier 28 will normrally exceed the constant speed of the peripheral surfaces of the embossing rolls 17, 18 while a i=tion of the web 1 between two successive imprinted portions advances through the nip of the rolls 17, 18; however, advancing means 14 speed of the rolls 18 begin to apply of the running web For the purposes of synchronization, particularly long-range synchronization, the function generator 31 receives signals from a photoelectronic detector 32 -which constitutes or forms part ef t the means for regulating the speed of the rolls of the advancing means 14 as a function of at least one parameter of the processing machine 46. The detector 32 monitors the path for the web 1, and more specifically the path for successive discrete blanks 30 which have been imprinted by the rolls 17, 18 and are about to be, or in the process o-.LO being, draped over success i -Ire7-.;, delivered arrays 44 of rod-shaped in the processin, machine 46.

articles - The rolis o..E the advancinz means 14 deliver successive the speed of the rolls forming part of the is lowered back to the peripheral 17, 18 not 'Later than when the rolls 17, a pattern to the adjacent portion 1.

11h coherent shorter (30b) or longer (30a) blanks into a further pneumatically operated magazine 33 which is followed by additional advancing means 34 including two rolls one of which is driven by a variable-s-;Deed prime mover 38, e.g., an electric motor. The exact length of the blanks entering the magazine 33 depends upon the selected second speed of the motor 27 for the rolls of the advancing means 14. Thus, a blank (such as 30a) will be longer if the second speed of the rolls forming part of the advancing means 14 is higher, and theblank (30b) will be shorter if the second speed of the rolls forming part of the advancing means 14 is lower.

The motor 38 further drives one roll of additional advancing means 36 located downstream of the advancing means 34 (as seen in the direction of advancement of the web 1 toward the processing machine 46). The rolls of the advancing means 34 are driven in svr,7hronis,-n with the rolls of the advancing means 36. 2he circuit 3 9 of the motor 38 includes an adjustable amplifier. which receives signals from a tachometer generator 41 or another suitable device serving to furnish sianals denoting the rotational speed of the motor 38. Another input of the amplifier 39 receives signals from the pulse generator 9, and a further input of the 1 2.0 39 receives signals from the function generator 31. - of the amplifier 39 receives s2 Still another inpu- Lgnals from the detector 32.

FIG. 1 further shows a perforating device 42 including two rotary components disposed at opposite sides of the path for the web 1, and a severing device 43 adjacent the path for the web 1 downstream of the advancing means 36. The device 42 can be of any known design and serves to provide the running web 1 with longitudinally spaced apart rows of perforations 52 (FIGS. 4 and 5) each extending transversely of the direction of advancement of the web 1 toward the processing machine 46. The device 43 cooperates with a set of circulating endless suction belt conveyors 37 to separate from the leader of the web 1 successive foremost blanks (such as 30a or 30b) by cutting across the web along longitudinally spaced apart lines 49 shown in FIGS. 4 and 5.

FIG. 41 shows that the rolls 17, 18 of the design impressing unit, 16 provide each of the relatively long blanks 30a with a two-piece design including a first portion 47 applied to one end portion of the respective blank 30a and a second portion 48 applied to the other end portJon of the respective blank 30a. The two end - -L - - J Dortions ---: --zc.n blank 30a together constitute a preselected first or des-'zn bearing section and L-he non-embossed 2.1 intermediate portion 51 of each blank 30a constitutes a non-impressed second section of the respective blank 30a. The length of the intermediate portions (non impressed sections) 51 of the blanks 30a is determined by the selected second speed of the motor 27 for the rolls of the advancing means 14 immediately downstream of the design impressing unit 16, and such speed is selected by the function generator 31 and is ef Jve while the web 1 advances between the peripheral sur-face of the embossing roll 18 and the recess 23 in the peripheral surface of the embossing roll 17, i.e., at a time when the web 1 is free to slide relative to the rolls 17 and 18.

FIG. 5 shows a portion of a narrower web which consists of a series of still coherent relatively short blanks 30b. The nature of the two-piece design 47, 48 which is impressed into each of the relatively blanks 30b of FIG. 5 is the same as that of the two piece design 47, ' 8 in a relatively long blank 30a of FIG. 4. The difference is that the intermediate portion (non-impressed section) 51 of each blank 30b is shorter than the intermediate portions 51 of the relatively lona blanks 30a o.E FIG.

that the function 311 has web 1 a relat-vel-.- low sz)ee-d, e.a., -he reason -'s e e d f o r t he a secend 2:L slightly exceeding the at least substantially constant peripheral speeds of the rolls 17, 18 while the web of FIG. 5 is caused to advance between the fully patterned peripheral surface of the roll 18 and the recess 23 in the partially patterned peripheral surface of the L I- L.

roll 17.

The lines 52 of perforations are provided to tacilitate the tearing of a first portion of an imprinted and separated blank 30 from the remaining portion, e.g., by a purchaser of a packet of cigarettes wherein the array of. e.a., twenty parallel cigarettes is draped into an inner envelope constituted by a deformed blank 30 and an outer envelope, not shown.

An imoortant advantage of the improved method and apparatus is that the length of the blanks (such as 30a and 30b) can be selected at will by transmitting appropriate signals from the function generator 31 to L.he amplifier 28 for the motor -17 which drives at least one roll of the advancing means 14, i.e., of the means for pulling -he web 1 through the nip of the embossing rolls 17, 18. The second speed is effective only while the web 1 is free to slide relative to the embossing -oils 17 and 18, i.e., the peripheral speed of the rolls - - L- -orming part of the advancing means 14- matches the peripheral speed of the rolls 17, 18 when the pattern 212 on the :L3b peripheral surface of the embossing roll 17 islocated opposite the patterned peripheral surface of the roll 18, namely when the rolls 1-7, 18 cooperate to impress -he spaced apart end portions the portions 47, 48 into 4 k of the still coherent blan'.",s (such as 30a or 30b) formina part of the web advancing --rom the source toward the processing machine 46.

Another important advantage of the improved method and apparatus is that the rolls 17, 18 of the design impressing unit 16 need not be replacea as long as the nature of patterns to be i.mpressed to relatively short blanks is the same as that of the patterns to be impressed into relatively long blanks or vice versa. Furthermore, the apparatus can apply designs to relatIvely wide or relatively narrow webs, as long as the width of the webs does not exceed the width of the recess 23. The narrow strips of patterns on the peripheral surface adjacent the axial ends of the roll 17 can be omitted if the rotational movements of the rolls 1-1, 18 are synchronized in any other suitable way, e.g., by mating gears affixed to the shafts for the rolls 17 and 18.

The non-imprinted portions or secz--o-s 51 of the relativeiv short blanks or long blanks (30a) can be dimens-on;-d in such a wa.: tha-E the,' are not visible to the =-,.,e the opens 1 lly a soft or hard cigarette packet.

As a rule, the apparatus will operate in such a way that a second speed which is selected by the function generator 31 exceeds the at least substantially constant peripheral speed of the embossing rolls 17, 18, i. e., lorming part of the the peripheral speed of the rolls 4 1 advancing means 14 will exceed the peripheral speed of the rolls 17, 18 while the advancing means 14 is in the process of pulling a non-impressed portion or section 51 of the web 1 relative to the peripheral surfaces of the rolls 17, 18.

The illustrated variable-speed electric motor 27 for one of the rolls forming part of the advancing means 14 can be replaced by any other suitable prime mover which can drive the rolls of the advancing means ".erab"y with raD4d transition 14 at two or- more dif f erent speeds p-reI L_ - between lower and higher speeds. This ensures that the length of the design-bearing end portions of successive blanks 30a or 30b is the same (i.e., the combined length of the portions 47 and 48 of a design in a shorter or longer blank 30b or 30a remains unchanged) but the variations of length of the non-impressed portions or sections 51 determine the actual length of the coherent blanks.

The maaa,-:,ines 4 and 34 exhibit the advantage that the peripheral speed of the advancing rolls forming part of the advancing means 14, 34 and 36 can be increased or reduced without subjecting the web 1 to excessive (or in fact any unnecessary) tensional stresses. For example, the peripheral speed of the rolls forming part of the advancing means 14 ca.- be readily increased above the peripheral speed of the embossing rolls 17, 18 when the rolls 17, 18 are not in the process of providing the adjacent-portion of a web 1 with a two-piece design (such as 47, 48) because the rolls of the advancing means 14 then simply draw the web from the inagazine 4 at a speed which can be higher than the peripheral speed of the rolls 17, 18, i.e., the unit 16 then does not interfere with movement of the web relative to the peripheral surfaces of the rolls 17 and 18.

The amplifiers, electric motors, RPM monitoring devices, pulse generator, detectors, perforator, severing means and pneumatically operated magazines in the apparatus of FIG. 1 are commercially available parts or assemblies and by themselves form no part of The same holds true for the blank 46 of FIG. 1. The magazine 4 can -E w e b 1 constituting the source o interfering with alterna t4Lng more ments of the web toward t"ne n_-z) the present invention. processing machine be omitted if the bobbin can be rotated without -apid and sio-,;er -zd,,,anceroll's '17 a_nd 13.

1(0 Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it -for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential c.-.armczeristics o-E the generic and specific aspects of the above outlined contribution to the art and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the appended claims.

21-1

Claims

CLAIMS:

1. A method of treating a web of deformable sheet material consisting of a succession of coherent blanks, comprising the steps of advancing the web longitudinally in a predetermined direction along a predetermined path; and impressing a design only into preselected sections of successive coherent blanks during advancement of said sections of successive blanks along a predetermined portion of said path.

Ilia

2. The method of claim 1, further comprising the steps of separating successive i=ressed blanks from a leader of the web downstream of said predetermined portion of said path, as seen in said direction, and converting the separated blanks into envelopes for arravs of rod-shaiDed artic-les.

3. The method of claim 1 of treating a web of deformable sheet material consistina of a succession of coherent blanks each of which includes Eirst and second end portions spaced apart from each other in said direction and an intermediate portion between the respective first and second portions, each olL said preselected sections including at- least one end portion of the respective blank.

4. The method of claim 3, wherein said impressing step comprises advancing the web through a nip between the peripheral surfaces of two embossing rolls in said predetermined portion of said path and driving said rolls at an at least substantially constant speed in a direction such th-z-successive increments of the peripheral surfaces advance in said predetermined direction during movement along said nip, said web advancing step including transporting the web in said direction at a speed at least approximating said at least substantially constant speed during advancement of said preselected sections of successive blanks along said portion of said path.

5. method of claim 4, wherein said web advancing step further comprises transporting the web at at least one second speed, different from said at least substantially constant speed, during advancement of said sections of successive blanks of the web toward said portion of said path.

6. The rnethod of claim 5, wherein said at one second speed exceeds said at least substantially constant si3eed.

-50

7. The method of claim 1, wherein said advancing step includes pulling the web in said direction at a second portion of said path downstream from said predetermined portion, as seen in said direction.

8. The method of claim 7, wherein said impressina step includes advancing the web through a nip defined by peripheral surfaces of two embossing rolls disposed at opposite sides of said predetermined portion of said path and driving said rolls so that the peripheral surfaces advance along said predetermined portion of the path in said direction and at said at least substantially constant speed, said step of pulling the web including engaging the web by peripheral surfaces of two rotary advancing rolls disposed at opposite sides of said second portion of said path and moving the peripheral surfaces of the advancing rolls at said at least substantially constant speed during advancement of preselected sections of successive blanks along said predetermined portion of said path and at at least one second speed during advancement of said sections of successive blanks toward said predetermined portion of said path.

1,31

9. The method of claim 8, wherein said moving step includes driving at least one of the advancing rolls by at least one variable-speed electric motor.

10. The method of claim 9, further comprising the step of regulating the peripheral speed of the advancing rolls as a function of at least one variable parameter of a web processing machine receiving successive blanks in a third portion of said path downstream of said second portion, as seen in said direction.

11. The method of claim 10, further comprising the step of selecting said at least substantially constant speed of the peripheral surfaces of the embossing rolls as a function of at least one variable parameter of the processing machine.

32-

12. The method of claim 1, further comprising the step of varying the length oil the blanks, as seen in said predetermined direction, including advancing the web at a first speed during advancement of preselected sections of successive blanks along said predetermined portion oll said pa--h and advancing the web at at least one different second speed during advancement of preselected sections of successive blanks toward said predetermined portion of said path so that each blank advancing beyond said predetermined portion of said path includes an impressed section of fixed 'Length and a second section having a length depending upon the second speed.

13. The method of claim 12, further comprising the steps of eneratJng signals denoting different second speeds and utilizing selected second signals to determine the second speed of the web during advancement of preselected sections of successive blanks toward said rrede--e---.nined Dortion of;aid nath.

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14. Apparatus for treating a web of deformable sheet material consisting of a succession of coherent blanks, comprising means for advancing the web longitudinally in a predetermined direction along a predetermined path; and means for impressing a design only into a preselected section of each of said succession o blanks, including cooperating first and second embossing rolls having peripheral surfaces and disposed at opposite sides of said path and means for driving a predetermined portion oi at least said first roll at a substantially constant speed in a direction such that successive increments of said peripheral surfaces move in said predetermined direction during movement along said predetermined portion of said path.

3L.t

15. The apparatus of claim 14, wherein at least one predetermined portion of the peripheral surface of one of said rolls has a pattern which impresses said design into said sections of successive blanks during advancement of said sections of successive blanks along said uortion of said path.

16. The apparatus of claim 15, wherein the peripheral surface of said one roll is further provided with a recess which alternates with said pattern in the circum- 0 lerential direction of said one roll.

17. The apparatus of claim 14 for treating a web consisting of coherent blanks each having first and second end portions spaced apart from each other in said predetermined direction and an intermediate portion between the respective end portions, each of said preselected sections including at least one end portion of the respective blank.

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18. The apparatus of claim 14, wherein said advancing means includes means for pulling the web in a second portion of said path downstream of said predetermined portion, as seen in said direction.

19. The apparatus of claim 18, wherein said means for pulling the web includes two advancing rolls having peripheral surfaces defining for the web a nip at said second portion of said path, and means for driving the peripheral surfaces of said advancing rolls at a first speed at least approximating said substantially constant speed and at least one different second speed.

20. The apparatus of claim 19, wherein said means for driving the peripheral surfaces of said advancing rolls includes a function generator actuatable to raise the speed of the peripheral surfaces of said advancing rolls from said first speed to a higher second speed at preselected intervals and for preselected periods of time.

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21. The apparatus of claim 14, further comprising means for regulating the peripheral speed of said first - L - embossing roll as a function of the speed of advancement of the web along a further portion of said path downstream of said predetermined portion, as seen in said direction.

22. The apparatus of claim 14, further comprising Eor a looped portion of the web immediately a magazine.1 or closely upstream of said predetermined portion of said path, as seen in said direction.

23. A method of treating a web of deformable sheet material, substantially as herein described with reference to the accompanying drawings.

24. Apparatus for treating a web of deformable sheet material, substantially as herein described with reference to the accompanying drawings.