US3293970A

US3293970A - Guillotine for cutting webs of plastics material sheeting

Info

Publication number: US3293970A
Application number: US478972A
Authority: US
Inventors: Brockmuller Friedrich Franz
Original assignee: Windmoeller and Hoelscher KG
Current assignee: Windmoeller and Hoelscher KG
Priority date: 1964-10-19
Filing date: 1965-08-11
Publication date: 1966-12-27
Anticipated expiration: 1983-12-27

Description

1956 F. F. BROCKMULLER 3,

GUILLOTINE FOR CUTTING WEBS OF PLASTICS MATERIAL SHEETING Filed Aug. 11, 1965 4 Sheets-Sheet 1 Invem or Dec. 27, 1966 F. F. BROCKMULLER GUILLOTINE FOR CUTTING WEBS OF PLASTICS MATERIAL SHEETING Filed Aug. 11. 1965 4 Sheets-Sheet 2 D-lorneys 1966 F. F. BROCKMULLER 3,293,970

GUILLOTINE FOR CUTTING WEBS 0F PLASTICS MATERIAL SHEETING Filed Aug. 11. 1965 4 Sheets-Sheet a In venor GUILLOTINE FOR CUTTING WEBS OF PLASTICS MATERIAL SHEETING United States Patent 3,293,970 GUILLOTINE FOR CUTTING WEBS OF PLASTICS MATERIAL SHEETKNG Friedrich Franz Erockmiiller, Lengcrich, Germany, assignor to Windmiiller & Hiilscher, Leugerich, Germany Filed Aug. 11, 1965, Ser. No. 478,972 Qlaims priority, application Germany, Oct. 19, 1964,

37,781 Claims. (Cl. 83-328) In known guillotines for use in processing paper webs, the web to be cut is moved and out between two cooperating knives, which are carried by and rotate with knife cylinders, which are arranged one over the other. In such guillotines, trouble may arise because the cut leading edge of the paper Web frequently adheres to the cutting edge of the lower knife and follows the same when the cut has been effected. In this case the paper web does not reach the conveyor which is provided for discharging the sheets of paper but causes a disturbance of the operation because the leading edge of the paper web follows the lower knife and is diverted from the desired direction of movement and moved into the area between the conveyor and the knife cylinder. To avoid this drawback, blast nozzles have been provided in guillotines of the described type, e.g., in the lower knife cylinder, in such a manner that the cut leading edge of the paper web is lifted from the surface of the knife cylinder after each cut by compressed air so that the paper web is reliably moved onto the conveyor which discharges the sheets of paper.

An air blast directed against the web, however, causes uncontrolled air movements, which result in an undesired fluttering of the web if the same consists of plastics material sheeting, particularly of a thin film of high flexibility. Such blast results also in a suction effect which may tend also to deflect the web. Thus, an air blast for supporting a continuously advancing web of plastics material has not proved satisfactory.

For this reason, other known guillotines for cutting plastics material webs, as well as known paper guillotines, comprise, e.g., a stationary lower knife and an upper knife which is slidable up and down. As there is no rotational movement of the knives, the conveyors may extend close to the cutting edge of the lower knife so that the difficulties which arise in guillotines having rotating knives as regards the transfer of the cut leading edge of the web onto the conveyor are avoided.

These guillotines, however, have the serious disadvantage that the out can be effected only when the web to be cut is at a standstill. This requires an intermittent advance of the web so that the output of the apparatus is much reduced in comparison to a guillotine which comprises rotary knives and severs the sheets from a continuously advancing web. Besides, an intermittent drive is known to be more expensive and subject to higher Wear than a continuous drive.

Thus, it is an object of the invention to provide a guillotine for cutting webs of plastics material sheeting which differs from the previous guillotines for cutting plastics material webs in that it is suitable for severing sheets from a continuously moving sheeting web without involving the difficulties described initially hereinbefore because means are provided for a reliable transfer of the plastics material web onto the conveyor for discharging the sheets cut from the web.

According to the invention, this object is accomplished in that each of the cooperating knives rotated in a manner known per so about an axis which is spaced from the web and extends transversely to the direction of advance of the web, and these knives sever sheets from the con- 3,2933% Patented Dec. 27, 1966 "ice tinuously advancing web, and are guided parallel to themselves, preferably in a position at right angles to the plane of the Web, and a supporting device is provided immediately behind the lower knife, considered in the direction of rotation, and revolves with said lower knife and is moved after the cutting operation outwardly beyond the circle described by the knife, which supporting device serves for lifting the leading end of the web and for guiding it to the conveyor which succeeds in the direction in which the web is conveyed. The supporting device ensures a mechanical lifting of the leading end of the web from the lower knife after the cutting operation and a mechanical support until this leading end of the web has reached the conveyor. Thereafter the supporting device is returned to such an extent that it is below the plane of the web during the next cutting operation.

In a development of the invention, the supporting device may consist of a rake, which is pivoted adjacent to its end which is the rear end in the direction of rotation, whereas the conveyor consists of a set of belt conveyors, in which the individual belts and reversing pulleys define gaps for the passage of the prongs of the rake. The design of the supporting device as a rake in conjunction with the passage gaps in the set of belt conveyors permits of a particularly reliable deposition of the leading end of the web on the conveyor because the prongs of the rake may be swung between the conveyors while the leading end of the web previously supported by the prongs of the rake is left on the conveyor. According to the invention it is further desirable to have the outward and return pivotal movements of the supporting device controlled by a rotatably mounted camwheel, which revolves in unison with the supporting device.

According to the invention, a plurality of supporting discs may be provided, which rotate with the lower knife about the same axis of rotation and serve for supporting the web adjacent to the guillotine so as to prevent a sagging of the web between the feed table and the conveyor also during the periods in which the web is not supported by the supporting device.

An illustrative embodiment of the invention will be described hereinafter with reference to the drawings, in which FIG. 1 is a top plan view showing the lower cutting assembly of the guillotine according to the invention and FIGS. 2 to 4 are sectional views taken along line II-II in FIG. 1 through the lower and upper cutting assemblies in different positions of the knife beams.

In the lower cutting assembly, two

gears

1 and 2 are firmly mounted on a shaft 5, which is rotatably mounted in walls 3 and 4 of the machine frame. A shaft 6 is rotatably mounted on the

gears

1 and 2 and carries a knife beam 7 provided with a lower knife 8. By means of a crank-slide arrangement, which is indicated at 15, the shaft 5 is coupled to a drive, not shown. A top knife is mounted in a knife beam 10, which is carried by a shaft 11, which is rotatably mounted in two

gears

12 and 13 of the upper cutting assembly. The

gears

12 and 13 are secured to a shaft 14, which is rotatably mounted in the walls 3, 4 of the machine frame, like the shaft 5.

To ensure that the

knives

8 and 9 are substantially at right angles to the web during their cutting action, so that a smooth out resulting in neat edges is performed, as by scissors, the guillotine according to the invention is provided with parallel-holding mechanisms, known per so, by which the

knife shafts

6, 11 are held parallel to themselves during their revolution between successive cutting operatious. The parallel-holding mechanism of the lower cutting assembly comprises three intermeshing gears 16 to 18, which are arranged on that side of the apparatus which is opposite to the drive side. The gear 16 is nonrotatably connected to the knife shaft 6. The shaft 5 extends with a clearance through the hub of the gear 17, which is secured to the machine frame 3 so that this gear is stationary during the operation of the machine. The idler 18 is rotatably mounted on a pin 19, which is secured in the gear 1. Similarly, the parallel-holding mechanism of the upper cutting assembly comprises three intermeshing gears 2022, which are disposed on the drive side of the apparatus. The gear 20 is nonrotatably connected to the knife shaft 11. The gear 21 is secured to the machine frame 4. The idler 22 is rotatably mounted on a pin which is secured in the gear 13.

The supporting and transfer rake according to the in vention comprises a plurality of lifting prongs 23, (which are interconnected by a crossbar 24. The connecting bar 24 is rotatably mounted with pins 25 in the

gears

1 and 2 of the lower cutting assembly. A camwheel 26 for operating the transfer rake is nonrotatably secured to a layshaft 27, which is rotatably mounted in the gear 1. A gear 28 is also nonrotatably mounted on the layshaft 27 and in mesh with the gear 17 and serves for rotating the camwheel 26. A roller 29 engages the camwheel 26 and is connected by a lever 30 to the connecting bar 24. A spring 31 is stressed between a pin 32, which is mounted in the gear 1, and a pin 33, which is secured to the connecting bar 24. By this spring, the roller 29 is constantly urged against the camwheel 26 so that the motion of the camwheel is transmitted to the transfer rake.

The mode of operation of the guillotine according to the invention is apparent from FIGS. 2 to 4. The plastics material web 34 is fed by a pair of feed rollers 35 in the direction of the arrow 36 across a feed table 37 to the guillotine and contacts the lifting prongs 23, which assume substantially the position shown in FIG. 2 during the cutting operation and shortly before the same. In the instantaneous position of the

knives

8 and 9 shown in F IG. 2, a cut through the plastics material web 34 has just been effected. The tips of the lifting prongs 23 are then just behind the cut leading edge of the plastics material web 34. While the sheet 38 which has been severed from the web 34 is being discharged by conveyor belts 39 at aspeed which is higher than that of the web, the roller 29 runs up on the lobe of the camwheel 26. As the rotation of the pairs of

gears

1, 2 and 12, 13 in the direction of the arrows is continued, the camwheel 26 is rotated by the gear 28, which is in mesh with the gear 17. As a result, the transfer rake, which is connected to the roller 29, is pivotally moved outwardly about the pins 25 (see FIG. 3). The web 34 is thus lifted by the lifting prongs 23 beyond its normal plane of conveyance and is deposited on the belt conveyors '39 as the rotation of the pairs of

gears

1, 2 and 12, 13 is continued (FIG. 4). During this operation, the tips of the lifting prongs 23 move between the conveyor belts 39 (see also FIG. 1) so that a reliable deposition of the web on the conveyor is ensured. When the web 34 has been deposited on the belt conveyors 39, a sagging of the web between the belt conveyors 39 and the feed table 37 is avoided by a plurality of rotating discs 40, which are secured to the shaft 5 and have substantially the same diameter as the

gears

1 and 2. These discs are provided with recesses 41 for receiving the transfer rake. To reduce weight, the discs may also be provided with one or more apertures 42, which may be circular. When a cycle of operation of the transfer rake has been terminated, the roller 29 has run off the lobe of the camwheel 26 during the continued rotation of the

gears

1 and 2 so that the lifting prongs 23 return to their position shown in FIG. 2, where they match the periphery of the discs 40.

When it is desired to vary the length of the sheets to be severed from the plastics material web, the crank-slide drive 15 enables an adjustment of the velocity of the

knives

8, 9 during the cutting operation in accordance with the changed velocity of the web. When very long plastics material sheets are to be produced, the peripheral velocity of the members which are rotated by the shaft 5 decreases when the cut has been effected but no difiiculties will be involved in the transfer of the web by the lifting prongs 23 onto the belt conveyors 39 although the feeding speed of the web 34 from the pair of feed rolls 35 exceeds the peripheral speed of the discs 40. When the tips of the lifting prongs 23 have been lifted, these tips have a larger peripheral velocity than the discs 40 because the tips are at a larger distance from the axis of rotation. This ensures that the web 34 will be held with sufiicient tautness in these cases too and will be reliably passed over onto the belt conveyors 39. Once the web has reached the belt conveyors 39, the tautness of the web as required for the cutting operation is ensured by the fact that the belt conveyors revolve at a velocity which is higher than that of the web.

What is claimed is:

1. A guillotine for cutting webbed material, said guillotine comprising a first knife beam rotatably mounted about an axis spaced above said material, a second knife beam rotatably mounted about an axis spaced below said material, said knife beams extending transversely to the direction of travel of said material and each carrying a blade, first moving means to move said beams along an arcuate path, second moving means to continuously advance said material between said blades so that said blades will simultaneously engage said material at periodic intervals to sever sheets from said material, conveying means to convey said sheets from said blades, at least one support member pivotally mounted about an axis spaced below said material and movable along an arcuate path similar to that of said second knife beam, and means to control the pivotable movement of said support member so that it lifts the leading end of said material and guides same to said conveying means after said severing.

2. The guillotine of claim 1 wherein said support member is in the form of a rake, the prongs of which lift and guide said material.

'3. The guillotine of claim 1 wherein said conveying means comprises a set of belt conveyors together defining gaps for passage of a portion of said support member.

4. The guillotine of claim 3 further comprising feeding means arranged upstream of said blades, and a plurality of supporting discs rotatably mounted about the same axis as said second knife beam and adapted to prevent the sagging of said web between said belt conveyors and said feeding means.

5. The guillotine of claim 1 wherein said means to control the pivotable movement of said support member comprises a camwheel adapted to move in unison with and engage said support member, and means to rotate said camwheel to move said support member according to a predetermined cycle.

References Cited by the Examiner UNITED STATES PATENTS 2,405,204 8/1946 Goodrich 83-337 2,693,630 11/1954 Rodder 83-327 3,079,826 3/1963 Shively 83337 FOREIGN PATENTS 906,536 3/1954 Germany. 484,082 5/1938 Great Britain.

WILLIAM W. DYER, JR., Primary Examiner. L. TAYLOR, Assistant Examiner.

Claims

1. A GUILLOTINE FOR CUTTING WEBBED MATERIAL, SAID GUILLOTINE COMPRISING A FIRST KNIFE BEAM ROTATABLY MOUNTED ABOUT AN AXIS SPACED ABOVE SAID MATERIAL, A SECOND KNIFE BEAM ROTATABLY MOUNTED ABOUT AN AXIS SPACED BELOW SAID MATERIAL, SAID KNIFE BEAMS EXTENDING TRANSVERSELY TO THE DIRECTION OF TRAVEL OF SAID MATERIAL AND EACH CARRYING A BLADE, FIRST MOVING MEANS TO MOVE SAID BEAMS ALONG AN ARCUATE PATH, SECOND MOVING MEANS TO CINTINUOUSLY ADVANCE SAID MATERIAL BETWEEN SAID BLADES SO THAT SAID BLADES WILL SIMULTANEOUSLY ENGAGE SAID MATERIAL AT PERIODIC INTERVALS TO SEVER SHEETS FROM SAID MATERIAL, CONVEYING MEANS TO CONVEY SAID SHEETS FROM SAID BLADES, AT LEAST ONE SUPPORT MEMBER PIVOTALLY MOUNTED ABOUT AN AXIS SPACED BELOW SAID MATERIAL AND MOVABLE ALONG AN ARCUATE PATH SIMILAR TO THAT OF SAID SECOND KNIFE BEAM, AND MEANS TO CONTROL THE PIVOTABLE MOVEMENT OF SAID SUPPORT MEMBER SO THAT IT LIFTS THE LEADING END OF SAID MATERIAL AND GUIDES SAME TO SAID CONVEYING MEANS AFTER SAID SEVERING.