US3757624A

US3757624A - Apparatus for severing sheet-like materials in machines for the processing of smokers product

Info

Publication number: US3757624A
Application number: US00258371A
Authority: US
Inventors: F Kruse; G Wahle; W Rudszinat; O Erdmann
Original assignee: Hauni Werke Koerber and Co KG
Current assignee: Koerber AG
Priority date: 1971-06-02
Filing date: 1972-05-31
Publication date: 1973-09-11
Anticipated expiration: 1990-09-11
Also published as: IT955740B; FR2141705A1; FR2141705B1; DE2127294A1; GB1389943A

Abstract

A cutting apparatus for subdividing webs of paper, metallic foil or synthetic plastic material into blanks or uniting bands for use in tobacco processing machines has an intermittently driven hollow drum which is open at one end and is formed with two openings located diametrically opposite each other. The external surface of the drum attracts by suction the leading end of a web which is being withdrawn from a bobbin. A stationary blade is mounted externally of the drum and a second blade is mounted in the interior of the drum opposite the stationary blade. When the drum is at a standstill, one of its openings (which is then overlapped by the leading end of the web to be severed) is located between the two blades. The second blade is then caused (either by an electromagnet or by a rotary cam) to move relative to the stationary blade whereby the cutting edges of the blades cooperate to sever the web overlying that opening which is located between the blades.

Description

Elll

Kruse et al.

tea aterrt [1 1 APPARATUS FOR SEVERING SHEET-LIKE MATERIALS IN MACHINES FOR THE PROCESSING OF SMOKERS PRODUCT [75] Inventors: Friedel Kruse, Hamburg; Giinter Wahle, Reinbek; Willy Rudszinat, Dassendorf; Otto Erdmann, Hamburg, all of Germany [73] Assignee: Hanuni-Werlre Korber & Co. KG,

Hamburg, Germany [22] Filed: May 31, I972 [2l] Appl. No.: 258,371

[30] Foreign Application Priority Data June 2, l97l Germany P 2l 27 294.6

[52] [1.8. CI. 83/271, 83/276 [51] Int. Cl B65h 35/06 [58] Field of Search 83/27l, 276, 267,

[56] Reterences Cited UNITED STATES PATENTS 3,654,828 4/1972 Leblond et a] 83/267 X Primary Examiner.l. M. Meister Attorney-Michael S. Striker [57] ABSTRACT A cutting apparatus for subdividing webs of paper, metallic foil or synthetic plastic material into blanks or uniting bands for use in tobacco processing machines has an intermittently driven hollow drum which is open at one end and is formed with two openings located diametrically opposite each other. The external surface of the drum attracts by suction the leading end of a web which is being withdrawn from a bobbin. A stationary blade is mounted externally of the drum and a second blade is mounted in the interior of the drum opposite the stationary blade. When the drum is at a standstill, one of its openings (which is then overlapped by the leading end of the web to be severed) is located between the two blades. The second blade is then caused (either by an electromagnet or by a rotary cam) to move relative to the stationary blade whereby the cutting edges of the blades cooperate to sever the web overlying that opening which is located between the blades.

13 Claims, 4 Drawing Figures PAIENTEU 3 757 624 sum 2 or 4 APPARATUS FOR SEVERHNG SHEET-LEKE MATERIALS TN MAQHINES FOR THE PROCESSING OF SMOKERS PRODUCT BACKGROUND OF THE INVENTION The present invention relates to apparatus for severing sheet-like materials in machines for the processing of smokers products. More particularly, the invention relates to improvements in apparatus for severing a continuous web of paper, foil or synthetic plastic material into sections or blanks of desired length. Still more particularly, the invention relates to apparatus for severing sheet-like materials for the purpose of producing a series of blanks or uniting bands which can be utilized in packing or wrapping machines for discrete smokers products or for wrapping or packing of arrays or blocks of plain or filter cigarettes, cigars or cigarillos.

Packing or wrapping machines for smokers products utilize one or more types of blanks which serve to form portions of or entire envelopes for discrete rod-shaped articles or for blocks or arrays of rod-shaped articles, such as plain or filter cigarettes. A pack for a block of cigarettes normally comprises an inner envelope consisting of tinfoil, an outer envelope which consists of paper or cardboard, and a further envelope which surrounds the paper envelope and normally consists of transparent synthetic plastic material with or without a tear strip. Cigars or cigarillos are often wrapped into transparent envelopes prior to being introduced into a box or an analogous container. As a rule, blanks of tinfoil or synthetic plastic material are formed by drawing a continuous web of such material from a bobbin and by severing the leading end of the web at regular intervals to form a succession of blanks which are thereupon manipulated to be converted into envelopes for discrete rod-shaped articles or for blocks of such articles.

Packing machines which operate in stepwise fashion normally employ a severing apparatus wherein a first knife is movable relative to a stationary second knife during each interval of dwell. Thus, when the conveyor system which transports a web of tinfoil or cellophane along a predetermined path is brought to a standstill, the movable knife performs a working stroke to cooperate with the stationary knife and to thus separate from the leading end of the web a blank of desired length. A take-off conveyor receives successive blanks for transport to a series of deforming or envelopeforming stations, and the supply conveyor thereupon advances the web by a step so as to place a predetermined portion of the leading end of the web beyond the common plane of the knives. A drawback of such severing apparatus is that the web and the blanks are transported by several conveyors so that the operation of several conveyors must be timed with a very high degree of accuracy. It happens again and again that the length of successively formed blanks deviates from an optimum length. This can cause serious problems in further processing; for example, a blank of tinfoil will be unable to properly surround a full block of plain or filter cigarettes.

it is also known to utilize in tobacco processing machines severing apparatus of the type wherein a suction conveyor in the form of a rotary drum is provided with a very hard and smooth external surface to which the leading end of the web adheres whereby the web shares the angular movements of the drum. A movable knife is adjacent to the periphery of the rotary drum and performs a succession of working strokes during each of which the edge of the movable knife cooperates with the hard external surface of the drum to sever a blank at the leading end of the web while the web adheres to the periphery of the drum. Such severing apparatus also exhibit a number of serious drawbacks. Thus, the severing action actually constitutes a squeezing of the web between the hard surface of the rotary drum and the edge of the movable knife. Consequently, the cuts are not as clean as is desirable in many types of packing machines for smokers products. Moreover, such severing apparatus are not suitable for the severing of certain types of materials, particularly for severing of very thin webs of cellophane or similar transparent synthetic plastic materials because the edge of the movable knife often fails to cut across the entire web. This causes lengthly interruptions in the operation of the packing machine with attendant losses in output.

It is further known to utilize in packing machines for cigarettes or the like a hollow rotary drum which rotates at a constant speed and accommodates a rotary knife. The drum is provided with an opening or window through which the knife passes at regular intervals in a predetermined angular position of the drum to cooperate with a stationary knife and to thereby sever a web of material which adheres to the periphery of the rotating drum. it was found that such types of severing apparatus are incapable of producing a succession of blanks each having a predetermined length. This is due to the fact that at least some slippage between the transported web and the periphery of the continuously rotating drum will take place while the knife which is mounted in the interior of the rotating drum performs a working stroke and cooperates with a stationary knife. Therefore, such apparatus failed to gain widespread acceptance in the tobacco processing industries.

SUMMARY OF THE INVENTION ticularly in packing machines for discrete tobaccocontaining smokers products or for blocks or arrays of rod-shaped smokers products.

Another object of the invention is to provide a severing apparatus which is capable of furnishing a succession of blanks or uniting bands consisting of paper, tinfoil or transparent synthetic plastic material whereby the length of each blank or uniting band either equals or at least very closely approximates an optimum length.

A further object of the invention is to provide an apparatus which can sever a web of paper, tinfoil or very thin synthetic plastic material in such a way that the cut is invariably clean and results in complete separation of a blank from the remainder of the web.

Still another object of the invention is to provide a novel and improved severing device for use in an apparatus of the above outlined character.

The invention is embodied in an apparatus for the severing of sheet-like material, particularly for subdividing continuous webs of wrapping or packing material into discrete blanks (which may but need not be coated with an adhesive) for use in packing or other processing machines for smokers products. The apparatus comprises a hollow rotary conveyor having an external material-retaining and advancing surface and at least one opening or window which is provided in such surface, severing means including a first cutting element which is outwardly adjacent to the external surface of the conveyor and a second cutting element which is mounted in the interior of the conveyor opposite the first cutting element, drive means for intermittently rotating the conveyor so that, during each period of dwell of the conveyor, a fresh portion of sheet-like material overlies the opening and the opening is located between the two cutting elements, and actuating means for moving one of the cutting elements relative to the other cutting element during each period of dwell of the conveyor to thereby sever the material which overlies the opening. The movable cutting element is preferably that element which is mounted in the interior of the conveyor. The actuating means for the movable cutting element may include an electromagnet having an armature which supports a holder or constitutes a holder for the movable cutting element, or a rotary cam having a peripheral surface which is tracked by a follower on the movable cutting element.

The novel features which are considered as characteristic of the invention are set forth in particulr in the appended claims. The improved severing 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 perusual of the following detailed description of certain specific embodiments with reference to the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a fragmentary schematic side elevational view of a packing machine for plain or filter cigarettes which embodies the improved severing apparatus, the rotary conveyor of the severing apparatus being shown in section;

FIG. 2 is a similar fragmentary schematic side elevational view of a packing machine which embodies a modified severing apparatus;

FIG. 3 is a fragmentary axial sectional view of a third severing apparatus; and

FIG. 4 is a sectional view as seen in the direction of arrows from the line IVIV of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to FIG. 1, there is shown a portion of a packing machine which provides cigarette packs with outer envelopes consisting of cellophane or analogous synthetic plastic material. The packing machine includes a source of transparent wrapping material here shown as a bobbin 4 containing a supply of convoluted web 3 of cellophane. The web 3 is being withdrawn from the bobbin 4 by a pair of advancing rolls 1 and 2 at least one of which is driven so as to advance the web 3 in the direction indicated by the arrow 3a. The advancing roll 2 cooperates with a rotary slitting or scoring knife 6 serving to provide longitudinally spaced portions of the web 3 with slits which are necessary in connection ith the application of customary tear strips, not shown. The web 3 advances along the periphery of the advancing roll 2 and is attracted to the cylindrical external surface 18 of an intermittently rotated conveyor 7 forming part of the improved severing apparatus. The conveyor 7 is a hollow drum which is shown as being rotatable about a horizontal axis and is providcd with two openings or windows 8 and 9 located diametrically opposite each other. The means for intermittently rotating the drum 1 in a clockwise direction, as viewed in FIG. 1, comprises a gear train including a gear 50 on the shaft of the drum 1. The manner in which the drum 1 can be mounted in the frame of the packing machine will be described in connection with FIGS. 3 and 4.

The severing apparatus further comprises a movable knife or cutting element 11 which is mounted in the interior of the hollow conveyor 7 and is reciprocable and- /or pivotable in bearings 11a. The directions in which the knife or cutting element 11 is reciprocable are indicated by a double-headed arrow 14. The actuating means for intermittently moving the knife 11 comprises a rotary cam 13 which is mounted on a shaft and has a peripheral surface tracked by a roller follower 12 at the inner end of the knife 11. A suitable spring, not shown, is provided to permanently bias the roller follower 12 against the periphery of the cam 13.

The severing apparatus further comprises a second cutting element or knife 15 which is outwardly adjacent to the cylindrical external surface 18 of the conveyor 7 and is mounted on a holder 19. The holder 19 is mounted on a supporting element or block 19a and is adjustable in directions indicated by a double-headed arrow 19b by means of two adjusting screws 21 mounted in the support 19a. To this end, the holder 19 is provided with several parallel elongated slots 19c for reception of guide pins 22 on the support 190. As shown in FIG. 1, tthe knife 15 has a substantially wedge-shaped front end portion 16 bounded by two inclined surfaces making an acute angle and defining an elongated cutting edge 16a. The outer end portion of the movable knife 11 is preferably of similar configuration. A further conveyor 17 severs to receive blanks 60 from the peripheral surface 18 of the intermittently rotating conveyor 7. The conveyor 17 may transport such blanks to a draping, folding, tucking or other station where the blanks are converted into outer envelopes surrounding complete packs of plain or filter-tipped cigarettes, not shown.

The conveyor 7 is a suction drum and is provided with a plurality of suction ports 7a which are connected with a suction generating device of known design so as to attract the leading end of the web 3 during transport from the station A where the web leaves the advancing roll 2 and station B where the leading end of the web 3 or the leading end of a freshly formed blank 60 reaches the conveyor 17.

The gear 50 drives the drum 7 in synchronism with intermittently driven advancing rolls 1 and 2, slitting knife 6, and conveyor 17. The prime mover which transmits torque to the gear 50 and to the shafts of components 1, 2, 6 and 17 can also drive the shaft 13a of the cam 13. However, the nature of the transmission between the prime mover and the shaft 130 is such that the shaft 13a is at a standstill in the illustrated angular position of the cam 13 and while the conveyor 7 is caused to rotate through and that the conveyor 7 is at a standstill when the cam 13 is caused to complete one full revolution in a clockwise or counterclockwise direction, as viewed in FIG. 1.

THE OPERATION When the advancing rolls 1 and 2 are in motion, they withdraw from the bobbin 4 a predetermined length of the web 3. The leading end of the web 3 passes through the nip between the advancing rolls 1 and 2 and is thereupon slitted by the knife 6 before it reaches the external surface 18 of the rotating conveyor 7. The suction ports 7a attract the leading end of the web 3 so that the web advances with the surface 18 and overlies the opening 9 when the conveyor 7 is brought to a standstill. The conveyor 7 is arrested in that angular position in which the opening 9 is located between the

knives

11 and 15 of the severing apparatus. The previously formed blank 60 is transported by the conveyor 17 at a speed which exceeds the peripheral speed of the conveyor 7 so as to separate the trailing portion of each preceding blank 60 from the leading portion of the next-following blank by a gap 61 of desired width.

When the conveyor 7 is brought to a standstill, the prime mover causes the shaft 13a to complete one revolution whereby the cam 13 shifts the movable knife 1 1 in a direction to the right, as viewed in FIG. 1, so that the cutting edge of the knife 11 cooperates with the cutting edge 16a of the stationary knife 15 and severs that portion of the web 3 which overlies the opening 9. The knife 11 is immediately retracted to the idle position shown in FIG. 1 so that the conveyor 7 is again free to rotate and to entrain and carry the leading end of the web 3 whereby the web overlies the opening 8. The same procedure is repeated again and again at regular intervals whereby the conveyor 17 receives a succession of blanks 60 each having a predetermined length.

The packing machine of FIG. 2 is very similar to that of FIG. 1 and all such component parts of the second machine which are clearly analogous to or identical with the corresponding parts of the machine shown in FIG. 1 are denoted by similar reference characters plus 100. The main difference between the severing apparatus of FIGS. 1 and 2 is that the actuating means for the movable knife 111 includes an electromagnet 124 having an armature 123 supporting a holder 123a for the knife 111. The electromagnet 1241 is energized or deenergized during the periods of dwell of the rotary drumshaped conveyor 107 so that the movable knife 111 then performs a working stroke and cooperates with the stationary but adjustable knife 115 to sever that portion of the web 103 which overlies the opening or

window

108 or 109 of the conveyor 107.

The signals for energization or deenergization of the electromagnet 124 can be furnished by the drive means for the conveyor 107, advancing

rolls

101, 102, slitting knife 106 and/or conveyor 117.

It is clear that the

conveyor

7 or 107 can be provided with a single opening or with three or more equidistant openings, depending on the desired length of the

blanks

60 or 160 and on the peripheral speed of the

conveyor

7 or 107.

The adjusting screws 21 or 121 render it possible to properly select the position of the

stationary knife

15 or 115 so as to insure the formation of clean cuts across the

entire web

3 or 103 when the

movable knife

11 or 111 is caused to perform a working stroke. It is clear that the movable knife 1 1 or 111 can also be adjustable relative to its holder; however, the construction shown in FIGS. 1 and 2 is preferred at this time because the

stationary knife

15 or 115 is always accessible, also when the apparatus is in use.

The apparatus of FIG. 1 exhibits the advantage that the actuating means for the movable knife 11 is very sturdy and can stand long periods of use. If desired, the

cam 13 of FIG. 1 can be rotated at a constant speed in such a way that the follower 12 tracks the circular portion 13A of the cam 13 while the conveyor 7 rotates and that the follower 12 tracks the lobe 13B of the cam 13 when the conveyor 7 is at a standstill. Thus, the follower 12 will cause the knife 11 to complete a working stroke and a return stroke only at such times when the follower tracks the lobe 1313. It is assumed that the actuating means for the knife 11 of FIG. 1 is operated in such a way that the cam 13 is at a standstill while the conveyor 7 rotates through 180, and that the cam 13 is caused to complete a full revolution when the conveyor 7 dwells in the angular position shown in FIG. 1 or in the other angular position in which the opening 9 is located between the

knives

11 and 15. It is further clear that the cam 13 can be replaced with a modified cam having two or more lobes so that the cam need not be rotated through a full revolution whenever the conveyor 7 is at a standstill. All such modifications will be readily understood by referring to the description of FIG. 1.

The apparatus of FIG. 2 exhibits the advantage that the wear upon the ctuating means for the movable knife 111 is negligible and also that the knife 111 can complete a working stroke and a return stroke within an extremely short interval of time. It is further clear that the cam 13 of FIG. 1 and/or the electromagnet 124 of FIG. 2 can be replaced by actuating means in the form of a cylinder and piston assembly which utilizes pressurized hydraulic or pneumatic fluid. The

movable knife

11 or 111 is then mounted on the piston rod of the cylinder and piston assembly and the cylinder of such assembly is preferably of the double-acting type so that it causes the

movable knife

11 or 111 to perform a working stroke when it receives pressurized fluid in one of its chambers. The

knife

11 or 111 is retracted into the

conveyor

7 or 107 when the other chamber of the cylinder receives a pressurized fluid.

The special configuration of the front end portion 16 or 116 of the

stationary knife

15 or 115 contributes to the formation of clean cuts across the

entire web

3 or 103.

The severing apparatus of FIGS. 3 and 4 comprises an intermittently rotated conveyor in the form of a hollow drum 207. The eb 203 to be severed is assumed to consist of transparent synthetic plastic material similar to that of the

web

3 or 103. The left-hand axial end of the conveyor 207 is open, as at 207d, and the other axial end 207s of the conveyor is mounted in a wall W of the machine frame in cantilever fashion. The means for intermittently rotating the conveyor 207 includes a shaft 207f which is secured to the end 207e. The conveyor 207 has a cylindrical external surface 218 and is provided with two openings or

windows

208, 209 which are located diametrically opposite each other and each of which is an elongated slot (compare FIGS. 3 and 4).

The movable knife 211 is mounted on a holder 226 which is pivotable or otherwise movable in the direction indicated by the arrow 214 to move the cutting edge of the knife 211 through the

opening

208 or 209 so that the knife 211 can cooperate with the stationary knife 215 which is outwardly adjacent to the peripheral surface 218 of the intermittently driven conveyor 207. As shown in FIG. 4, the stationary knife 215 is provided with elongated slots 2190 for the stems of bolts 222 which mesh with a holder 219. The cutting edge 216a of the stationary knife 215 is closely adjacent to the peripheral surface 218 of the drum 207 and is defined by two surfaces making an acute angle. At least when the movable knife 211 is at a standstill, the elongated cutting edge 227 of the knife 211 is slightly inclined relative to the cutting edge 216a of the stationary knife 215 (see FIG. 3). The knives 211 and 21S constitute the blades of a pair of shears and the cutting action performed by the edges 2160, 227 is such that the cutting of a web 203 begins along the left-hand marginal portion of the web, as viewed in FIG. 3, and progresses toward the right-hand marginal portion.

The holder 226 for the movable knife 211 is a plate (see FIG. 4) which is connected with a retainer 228 for one or more helical springs 233 which react against a lever 229. The retainer 228 constitutes one leaf of a hinge having a pintle 232 and a second leaf 231 secured to the lever 229. The axis of the pintle 232 is parallel to the axis of the conveyor 207. The spring or springs 233 tend to pivot the leaf 228 in a clockwise direction, as viewed in FIG. 4. This causes a projecting portion 234 of the movable knife 211 to constantly abut against the adjacent portion of the stationary knife 215. As shown in FIG. 3, the projecting portion 234 is outwardly adjacent to the open end 207d of the intermittently rotating conveyor 207.

A portion of the lever 229 extends into the interior of the conveyor 207 through the open end 207d and supports the holder 226 by way of the hinge 230. This lever is pivotable in the housing or frame of the machine on a horizontal shaft 236 which is parallel to the pintle 232 and to the axis of the conveyor 207. A roller follower 212 on the lever 229 tracks the peripheral surface ofa cam 213. A helical spring 237 is connected to the stationary holder 219 for the knife 215 and to the lever 229 so as to permanently bias the roller follower 212 against the periphery of the cam 213. The outline of the cam 213 is clearly shown in FIG. 4; this cam is mounted externally of the drum 207 on a shaft 239 and is connected with a driver gear 238. The gear 238 is driven at a constant speed and the configuration of the cam 213 is such that it causes the movable knife 211 to perform a working stroke and to cooperate with the cutting edge 216a of the stationary knife 215 when the conveyor 207 is at a standstill and the

opening

208 or 209 is located between the cutting

edges

216a and 227.

The operation of the severing apparatus of FIGS. 3 and 4 is as follows:

When the packing machine is in operation, the conveyor 207 is rotated intermittently, always through an angle of 180 to thereby advance the web 203 through a predetermined distance and to cause a portion of the web to overlie the

opening

208 or 209, namely, that opening which is located between the cutting

edges

216a and 227 when the conveyor 207 is at a standstill. When the conveyor 207 rotates, the roller follower 212 of the lever 229 tracks the circular portion 213A of the peripheral surface on the continuously rotating cam 213. When the conveyor 207 is at a standstill, the roller follower 212 tracks a flat portion 213B of the peripheral surface on the continuously rotating cam 213 whereby the spring 237 is free to contract and causes the movable knife 211 to cooperate with the stationary knife 215 so as to sever that portion of the web 203 which overlies the

opening

208 or 209, namely, that opening which is located between the cutting

edges

216a and 227. When the lever 229 is free to pivot under the action of the spring 237, the movable knife 211 moves about the pivot axis of the shaft 236 relative to the stationary knife 215 whereby the two knives cooperate not unlike the blades of a pair of shears. As mentioned before, the projecting portion 234 of the movable knife 211 is caused to bear against the adjacent portion of the statonary knife 215 under the action of the spring or springs 233. TThis insures that, when the lever 229 pivots in a clockwise direction, as viewed in FIG. 4, successive increments of the cutting edge 227 slide along successive increments of the stationary cutting edge 216a to sever the web 203 all the way from the one to the other marginal portion thereof. The hinge 230 further serves to compensate for the fact that, when it performs a working stroke, the movable knife 211 pivots about the axis of the shaft 236 for the lever 229. When the severing of the web 203 in the region of the

opening

208 or 209 is completed, the continuously rotating cam 213 moves its portion 213a against the roller follower 212 whereby the movable knife 211 is automatically retracted into the interior of the conveyor 207 before the conveyor begins to rotate so as to move the opening 209 (see FIG. 4) into the space between the cutting

edges

216a and 227.

The severing apparatus shown in FIGS. 3 and 4 exhibits several important advantages. Thus the supporting means for the movable knife 211 can be mounted in the machine frame externally of the intermittently rotated conveyor 207. Therefore, the diameter of the conveyor 207 need not be increased for the express purpose of accommodating a large number of parts of the severing apparatus.

All embodiments of the improved severing apparatus share the advantage that the cutting operation takes place when the conveyor which transports the web to be severed is at a standstill. This greatly reduces the likelihood of producing blanks of different lengths. As mentioned before, a continuously rotating conveyor is likely to cause at least some slippage of the web while the movable knife performs a working stroke. It is further within the purview of the invention to utilize a stationary knife in the interior of the rotary conveyor and to place the movable knife adjacent to the external surface of such conveyor. This would merely amount to a simple reversal of functions of the two cutting elements.

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 which fairly constitute essential characteristics of the generic and specific aspects of our contribution to the art and, therefore, such adaptations should and are intended to be comprehended within the meaning and the range of equivalence of the claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims.

We claim:

1. Apparatus for severing sheet-like material, particularly for subdividing continuous webs of wrapping material into discrete blanks in packing or other processing machiens for smokers products, comprising a hollow rotary conveyor having an external materialretaining and advancing surface and at least one opening in said surface; severing means including a first cutting element outwardly adjacent to said surface of said conveyor and a second cutting element mounted in the interior of said conveyor opposite said first cutting element; drive means for intermittently rotating said conveyor so that, during each period of dwell of said conveyor, a fresh portion of sheet-like material overlies said opening and the opening is located between said cutting elements; and actuating means for moving due of said cutting elements relative to the other cutting element during each period of dwell of said conveyor to thereby sever the material overlying said opening.

2. Apparatus as defined in claim 1, wherein said conveyor is a hollow cylinder and said one cutting element is said second cutting element.

3. Apparatus as defined in claim 1, wherein said actu' ating means includes means for maintaining said one cutting element at a standstill while said conveyor rotates.

4. Apparatus as defined in claim 1, wherein said conveyor is a hollow cylinder having an open end, said actuating means including a holder for said second cutting element, said holder being mounted without said cylinder and having a portion extending through the open end and into the interior of said cylinder, said second cutting element being mounted on said portion of said holder.

5. Apparatus as defined in claim 1, wherein said severing means constitutes a pair of shears and each of said cutting elements constitute one blade of said pair of shears.

6. Apparatus as defined in claim 1, wherein a portion of said second cutting element continuously abuts against said first cutting element and said elements have elongated cutting edges which sever the material overlying said opening during movement of said one cutting element relative to said other cutting element.

7. Apparatus as defined in claim 6, wherein said severing means further comprises means for biasing successive increments of said cutting edges against each other during movement of said one cutting element.

8. Apparatus as defined in claim 1, wherein said one cutting element is said second cutting element and further comprising adjusting means for changing the position of said first cutting element relative to said conveyor and relative to said second cutting elementv 9. Apparatus as defined in claim 1, wherein said actu ating means comprises a rotary cam and follower means operatively connected with said one cutting element and arranged to track said cam.

10. Apparatus as defined in claim 1, wherein said actuating means comprises electromagnet means having an armature movable between first and second position to thereby move said one cutting element relative to said other cutting element.

11. Apparatus as defined in claim 1, wherein at least one of said cutting elements has an elongated blade provided with a pair of surfaces making an acute angle and defining an elongated cutting edge.

12. Apparatus as defined in claim 1, wherein said surface of said conveyor has a plurality of angularly spaced openings and said drive means is arranged to rotate said conveyor through angles corresponding to angles between successive openings of said surface.

13. Apparatus as defined in claim 1, wherein said conveyor comprises means for attracting sheet-like material to said surface.

Claims

1. Apparatus for severing sheet-like material, particularly for subdividing continuous webs of wrapping material into discrete blanks in packing or other processing machiens for smokers'' products, comprising a hollow rotary conveyor having an external material-retaining and advancing surface and at least one opening in said surface; severing means including a first cutting element outwardly adjacent to said surface of said conveyor and a second cutting element mounted in the interior of said conveyor opposite said first cutting element; drive means for intermittently rotating said conveyor so that, during each period of dwell of said conveyor, a fresh portion of sheet-like material overlies said opening and the opening is located between said cutting elements; and actuating means for moving one of said cutting elements relative to the other cutting element during each period of dwell of said conveyor to thereby sever the material overlying said opening.

3. Apparatus as defined in claim 1, wherein said actuating means includes means for maintaining said one cutting element at a standstill while said conveyor rotates.

8. Apparatus as defined in claim 1, wherein said one cutting element is said second cutting element and further comprising adjusting means for changing the position of said first cutting element relative to said conveyor and relative to said second cutting element.

9. Apparatus as defined in claim 1, wherein said actuating means comprises a rotary cam and follower means operatively connected with said one cutting element and arranged to track said cam.