Field of Invention:

The present invention relates to paperconverting machinery and more particularly it relates toa digital synchro cross-cutting unit for folio size sheeterto reduce inertia of rotary drum and power consumption required to drive rotary drum and increase the cutting speed of machine for different paper size format.

Background of the Present Invention:

Cross cutting machines are known in the art in which the cutter knives operate with an irregular speed so that, for a variable rotary speed adjusted according to sheet length, the cutting speed of the cutter knives is constant. In general, in such arrangements the speed of the travelling paper web is constant and the rotary speed of the cutter knives during the cutting period is synchronized with the speed of travel of the web while by an acceleration or retardation of the rate of rotation of the cutter knives during the idle or non-cutting period and the consequent alteration of the cutter knife speed, the corresponding, adjustment of the sheet length is obtained.

In cross cutting machines of this type where the knives are carried on drums, the dimensions of the drums must be so selected that flexure thereof by the cutting pressure is avoided and likewise, particularly where the width of the web being cut is substantial, the cutter drums must have substantial dimensions to prevent this flexure as a result of the large inherent weight of the drums.

To avoid flexure of the drums, they are consequently provided with a large cross section and are of a correspondingly great or high weight. This weight must be accelerated and retarded during the course of one rotation of the drum. The torques resulting from the acceleration and retarding or deceleration of the drum stress the bearings of the machine as well as the gearing to a substantial extent, particularly where high operating speeds are employed so that the stressed parts are subjected to rapid wear or the output of the machine is reduced since the speed must be lowered to prevent wear. Further, such high weight rotary drum requires more power for generating sufficient torque and inertia.

A lowered output speed does not suffice to meet the requirements of an economically operated cross cutting machine. Another disadvantage of this known arrangement using heavycutter drums, lies in the fact that the forcesproduced by the acceleration and retardation of the drum are transmitted to the entire machine which is thus subjected to undesirable oscillation or vibration.

Hence, to overcome these deficiencies, a need exist for cross-cutting unithaving a construction to reduce the inertia of the rotary and reduce the overall power consumption of the rotary.

Object of the Present Invention:

The main object of the "a digital synchro cross-cutting unit for folio size sheeter" is to overcome the problem associated with conventional synchro cross cutting machines by providing a hollow rotary design of the rotary drums to reducing inertia and power consumption required to drive rotary drum and increase the cutting speed of machine.

Another object of the present invention is to increase the cutting speed of the machine and provide a very wide range of ratios to cut different size folio sheet.

Another object of the present invention is to eliminate the backlash between the gear trains for a specific revolution of the two rotaries.

Yet another object of the present invention is toimprove a service life of the machine.

These and other objects will be apparent based on the disclosure herein.

Summary of the Present Invention:

The present invention relates to a digital synchro cross-cutting unit for folio size sheeter. The digital synchro cross cutting unit according to present invention comprises a structure for synchro rotary consisting of a LH plate and a RH plate mounted on a base plate at distal end in such a manner that an angle is formed between direction of paper web through the web guide plate and the axis of a center shaft.

The digital synchro cross cutting unit further comprises a top rotary drum and a bottom rotary drum mounted below the top rotary drum.Both rotary drums are made of hollow honed tubes. Both rotaries are having hollow construction. The main purpose of the hollow rotary design of the present invention is to reduce the inertia of the rotary and to reduce the overall power consumption of the synchro rotary is too optimal. Therefore, the size of the servomotor becomes optimal. Low rotary inertia increases cutting speed for different paper size formats.

The digital synchro cross-cutting unit apparatus and of crosscutting of folio size sheeterof the present invention provides multiple benefits to the end users which are described in the following pages of specification.

Brief Description of Drawings:

Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the present embodiment when taken in conjunction with the accompanying drawings.

Fig.l is perspective view of a digital synchro cross-cutting unit for folio size sheeter according to present invention.

Fig. 2 is cross section view of a digital synchro cross-cutting unit for folio size sheeter according to present invention.

Fig. 3 is top view of a digital synchro cross-cutting unit for folio size sheeter according to present invention.

It should be noted that the figures are not drawn to scale and that elements of similar structures or functions are generally represented by reference numerals for illustrative purpose throughout the figures. It should also be noted that the figures are only intended to facilitate the description of the preferred embodiments. The figures do not illustrate every aspect of the described embodiments and do not limit the scope of the present disclosure.

Detailed Description of Present Invention:

Before explaining the present invention in detail, it is to be understood that the invention is not limited in its application to the details of the construction and arrangement of parts illustrated in the accompany drawings. The invention is capable of other embodiment, as depicted in different figures as described above and of being practiced or carried out in a variety of ways. It is to be understood that the phraseology and terminology employed herein is for the purpose of description and not of limitation.

It is to be also understood that the term "comprises" and grammatical equivalents thereof are used herein to mean that other components, ingredients, steps, etc. are optionally present. For example, an article "comprising" (or "which comprises") components A, B, and C can consist of (i.e., contain only) components A, B, and C, or can contain not only components A, B, and C but also contain one or more other components.

Now as shown in Fig.l and Fig. 3, the digital synchro cross cutting unit according to present invention comprises a structure (14) for synchro rotary consisting of a LH plate (19) and a RH plate (20) mounted on a base plate (29) at distal end in such a manner that an angle is formed between direction of paper web (30) through the web guide plate (31) and the axis of a center shaft (7, 7a). This angle compensates for the loft angle of the knives to cut the paper straight in the cross direction of the web.

The digital synchro cross cutting unit further comprisesa top rotary drum (1) and a bottom rotary drum (2) mounted below the top rotary drum (l).Both rotary drums (1, 2) are made of hollow honed tubes. Both rotaries(l, 2) are having hollow construction. The main purpose of the hollow rotary design of the present invention is to reduce the inertia of the rotary and to reduce the overall power consumption of the synchro rotary is too optimal. Therefore, the size of the servomotor becomes optimal. Low rotary inertia increases cutting speed for different paper size formats.

Referring to Fig. 2 of the present embodiment, a center shaft (7) is mounted inside and along the top hollow rotary drum (1). A center shaft (7a) is mounted inside and along the bottom hollow rotary drum (2). Both rotary drums (1, 2) are assembled on the central shaft(7, 7a) by double bearings (23) at each end of the rotary drums(l, 2) on the LH plate (19) and the RH plate (20). Both rotaries (1, 2) are connected to each other by gearbox housing (5) at each end of the rotary. The central shafts (7, 7a) are supported by on the LH plate (19) and the RH plate (20) through the gearbox housing (5). The center shaft (7, 7a) is locked with flanges (28) and the flanges (28) are locked with side plates the LH plate (19) and the RH plate (20) so the center shaft (7, 7a) remains stable and provide axial support to rotary drums (1, 2) during operation. A servo motor (3) is assembled on a main structure (14) by a servo motor flange (11).

Referring to Fig. 1 and 2, thegear box housing (5)mounted on the LH plate (19) and the RH plate (20). Both sides of the gear box housings (5)are connected by an oil level equalizer (8) to maintain the oil level in the gear box housing (5) with lubrication oil for helical gears. An oil drain plug (9) is provided at both end of the LH plate (19) and the RH plate (20). Saidoil level equalizer (8) is provided at the bottom of the main structure (14) which is connected to the bottom of both the gearbox housing (5) by a 11 " size of pipe. It is mounted at lower height and middle of both gearbox housing (5). The function of the oil level equalizer (8) is to maintain the same level of oil by the principle of gravity. An oil seals (18) is provided to prevent oil leakage from the rotary drums (1, 2).

Referring continuous Fig. 2, said gearbox housing (5) comprises a helical drive gear (27), a helical driven gear (24) being in engaged with helical drive gear (27) and a helical split gear (22) being in engaged with the helical driven gear (24).

The helical drive gear (27) is mounted on the LH plate (19) just above the top rotary drum (1) and engaged with the helical driven gear (24). The extended shaft of the helical drive gear(27) is directly connected to the servo motor (3) shaft by a shrink disc coupling (10). The servo motor (3) drives both rotaries by helical drive gear (27).

Referring continuous Fig. 2, the top rotary drum (1) and the bottom rotary drum (2) are connected to the helical driven gear (24) and the helical split gear (22) at each end of rotary locked with rotary drums (1, 2) with use of a fasteners bolts (not shown). The helical driven gear (24) and the helical split gear (22) are engaged to each other. The purpose of helical split gear (22) is to set backlash when helical driven gear (24) and the helical split gear (22) engaged together. The helical gears are located inside the gearbox housing (5) at each end of the rotary. The gear ratio between the top rotary drum (1) and the bottom rotary drum (2) is 1:1. These gear trains aredriven by a servo motor (3).

Referring continuous Fig. 2, atop rotary knife (6) is mounted along the top rotary drum (1) and a bottom rotary knife (7) is mounted along the bottom rotary drum (2). Both knives (6, 7) are engaged with each other to cut thepaper passing through rotaries.An angle between direction of web and the axis of the center shaft (7) compensates for the loft angle of the knives (6, 7) to cut the paper straight in the cross direction of the web. The paper web comes through the web guide plate (31) from a main pulling roller (not shown) and passes through the top rotary drum (1) and the bottom rotary drum (2).

Referring continuous Fig. 2, the rotary drums (1, 2) are supported by the numbers of guide pieces (25), which are mounted on the center shaft (7, 7a) at regular intervals. These guide pieces (25) provide a bearing surface to the rotary throughout the length of the rotary. Therefore, it prevents any deviation of rotary at time of cutting load and control run out of rotary throughout of rotary length. The gear trains are covered by split housing (13) mounted on the LH plate (19) and the RH plate (20), so that it can form closed gearbox housing (13).

Referring continuous Fig. 2, an O-ring (22) is also provided to prevent sealing between the helical gears and the rotary drums (1, 2), as the cavity between the center shaft (7, 7a) and the rotary drums is filled with the gearbox. Lubrication Oil is filled in gearbox for continuous lubrication for gears. The top rotary knife (6) has an angular adjustment between the hollow honed tube (top rotary drum (1)) and the helical driven gears (24) locking provided by the fasteners ofa locking assembly (12) at each endto match the top rotary knife (6) with the bottom knife (7). This matching is necessary to create zero clearance between the knives (6, 7) during rotation for perfect paper cutting. Which will improve the cut quality of the paper and maintain the reliability of the cutting quality until the life of the knives (6, 7) is re-grinded. This adjustment is also useful when knives (6, 7) become shorter after multiple grinding of the knives (6, 7) and for taking a re-impression of the knives (6, 7).

Referring continuousFig. 2,fhe bottom rotary drum (2) is provided with the nylon pieces (15) mounted an on outer surface thereof for support of paper web at regular intervals throughout the rotary length. The strips of wool felt are wrapped on the nylon support pieces (15). This arrangement supports the leading length of paper which is coming out of the rotary before the cutting operation. Therefore, it will prevent sagging of paper at high-speed operation.

It is to be noted that there should be no backlash between the gear trains for a specific revolution of the two rotaries. Therefore, the helical split gear (22) is designed into two parts and there is an eccentric pin between the two parts of gears to remove the backlash of the gear train. It is useful to remove initial backlash of gear train as well as after wearing of gear tooth.

Referring continuous Fig. 2, on the RH plate (20) side of the synchronous rotary, a teethsplit helical gear (16) is mounted just above the top rotary drum (1) and engaged to the top rotary gear train (helical gears) of the gearbox housing mounted on the RH plate. Anencoder (17) is mounted on extended shaft of the teeth split helical gear (16). It will transfer the rotary speed to the encoder (17). This encoder (17) is placed to generate feedback of the specific rotation of the rotary and send it to the main controller to monitor and control the rotary RPM. Therefore, more precise synchronization of rotary with web speed can be done to achieve accurate cut size.

The present invention has beneficial advantages that it reducesthe moment of inertia of rotating drums itself which facilitates optimum power consumption to drive the Rotary and efficient output speed for different size of papers. Further, the present invention eliminates the periodic maintenance and lubrication and it is improves the service life of the machine.

In the present invention the sheet length setting has been simplified with the integration of touch screen and PLC components. Simply to set the desired cut length and press the automatic sheeting length setting tab to run the machine and output the required cutting length.

The invention has been explained in relation to specific embodiment. It is inferred that the foregoing description is only illustrative of the present invention and it is not intended that the invention be limited or restrictive thereto. Many other specific embodiments of the present invention will be apparent to one skilled in the art from the foregoing disclosure. All substitution, alterations and modification of the present invention which come within the scope of the following claims are to which the present invention is readily susceptible without departing from the invention. The scope of the invention should therefore be determined not with reference to the above description but should be determined with reference to appended claims along with full scope of equivalents to which such claims are entitled.

LIST OF REFERENCE NUMERALS:

1 Top Rotary Drum

2 Bottom Rotary Drum

3 Servomotor

4 Top Helical Gear

5 Gearbox Housing

6 Top Knife

7 Bottom Knife

8 Oil Level Equalizer

9 Oil Drain Plug

10 Coupling

11 Servo Motor Flange

12 Locking Assembly

13 Housing

14 Structure for Synchro Rotary

15 Nylon Paper Support

16 Teeth Split Helical Gear

17 Encoder

18 Oil Seal 19 LH Plate

20 RH Plate

21 O-ring

22 Helical Split Gear 23 Bearing

24 Helical Driven Gear

25 Guide Piece

26 Center Shaft

27 Helical Drive Gear 28 Flanges For Shaft Support

29 Base Plate

30 Web Direction

31 Web Guide Plate