US2738842A

US2738842A - Web cutting apparatus for printing machines and the like

Info

Publication number: US2738842A
Application number: US335337A
Authority: US
Inventors: William F Huck
Original assignee: HUCK CO
Current assignee: HUCK CO
Priority date: 1953-02-05
Filing date: 1953-02-05
Publication date: 1956-03-20
Anticipated expiration: 1973-03-20

Description

March 20, 1956 w p c 2,738,842

WEB CUTTING APPARATUS FOR PRINTING MACHINES AND THE LIKE Filed Feb. 5, 1955 2 Sheets-Sheet l INVENTOR:

WILL/AM f. HucK BY W A ORNEY W. F. HUCK March 20, 1956 WEB CUTTING APPARATUS FOR PRINTING MACHINES AND THE LIKE 2 Sheets-Sheet 2 Filed Feb. 5, 1955 INVENTOR I WEB WIDTH WILLIAM} E Huck BY W ATTORNEY United States Patent F WEB CUTTING APPARATUS FOR PRINTING MACHINES AND THE LIKE William F. Huck, New York, N. Y., assignor to Huck Co.,'a partnership of New York, composed of William F. Huck, Alexander J. Albrecht, and Stephen S. Welteman i a Application February 5, 1953, Serial No. 335,337

2 Claims. (Cl. 164-67) This invention pertains to improvements in apparatus for handling webs ofpaper and the like, and particularly to improved web cuttingapparatus incorporated in high speed web printing, folding, cutting and delivery machinery. This application is a continuation-in-part of an earlier filed application, Serial No. 732,247, filed March 4,

1947, now Patent No. 2,659,437. issued November 17,

plished without interrupting the travel of the web throughthe machine, by knives mounted upon rolls or rollers between which the web passes. The present invention has for its object to disclose details of the structure of the knives, and their associatedparts, by which cutting is accomplished in an efficient manner, and without injuring the cut edges, and by apparatus which does not involve extreme accuracy of placement of the cutting knives them-- selves. The way in which the present invention is combined with the other essential parts of the complete han dling apparatus will be in part described herein, but for more complete details, especlally of the parts, which do not form a direct part of the present invention, reference may be made to the earlier application identified above. j The invention itself will best be understood by referring to the followingspecification of a preferred embodiment.

thereof, taken 'in connection with the appended drawings, in which: Fig. 1 is a fragmentary lateral sectional view of a pair of rolls each carrying one knife of a pair of cutting knives between which the web to be cut is passed,

Fig. 2 is a similar view but with the parts advanced" to'a position in which the cutting edges are actually engaged to cut the web,

Fig. 3 is a fragmentary front'elevation of the parts shown in Figs. 1 and 2,

2,738,842 Patented Mar. 20, 1956 ICC recess in the cylinder 16, where gripping fingers assist in forwarding the edge of the web.

The actual cutting of the web is thus accomplished by pairs of knives carried by the roller 15 and the cylinder 16, and as detailed in the prior application above, the roller 15 may carry a pair of knives located 180 apart on its periphery, while cylinder 16 may have, for example, three pairs of knives, the two rollers being driven so that one knife of each roller approaches a knife of the other roller to elfect the cutting of the web as it travels between said rollers. In detail, as the web W passes around cylinder 16, it is acted upon by the coacting cutting knives 35 and 36 carried by the roller and cylinder respectively. Each of the knives 36 on the cylinder 16, is positioned entirely below the surface of the cylinder 16 and each blade has a straight cutting edge that is parallel with the axis of cylinder 16. Each of the knives 35 on the cylinder 15 is a V-shaped, as best seen in Fig. 2. By this arrangement, which is known as involute cutting, the knives start to cut the web W simultaneously at both outer edges as the knives start to engage, and the cutting progresses in wardly from the edges of the web until the two cuts join at the center of the web, at which instant a sheet becomes completely severed from the web W. This method of cutting produces a perfectly straight cut. Each of the knives 36 is mounted for limited pivotal movement by means of a fulcrum groove 31 (Fig. 3) that cooperates with a fulcrum tongue 39 formed on one side of a support bar 34 that is secured to the cylinder 16 by a plurality of bolts, and by having a compression spring 37 that biases the knife 36 against a stop formed on the bar 34.

The. cylinder 16 is provided with a plurality of clearancespaces 43 each being located in a leading position ahead of each of the knives 36. As the web is severed by the knives 35 and 36 (Fig. 3), the trailing cut edge of the sheet being cutoff is forced by the forward face of the knife 35 to enter the recess 43 (see Fig. 2). At the same time the leading cut edge of the web from which the sheet is being cut is forced by a tucking blade 46 (Fig. 2) into a position leading the gripper 47. This position is in a recess formed in the cylinder 16 in afposition trailing the knife 36. The tucking blades 46 are carried by the cutting roller 15 in a parallel trailing relationship to the knives 35 and are held in position by the bolts 42 which are the same bolts that hold the knives 35 in place. A short time thereafter a row of fingers 49 (Fig. 2) which are made of Fig. 4 is an enlarged elevational view showing the V- knives carried by the rolls of Figs. 1 and 2,

Fig. 5 is .a cross-sectional view taken on .line 5-5 of Fig. 4, e

Fig. 6 is a fragmentary perspective view showing the configuration of the forward endof the V-blade.

Referring first to Figs. 1 to 3 of the drawings, a portionof the web handling machine is shown, including spring metal and carried by the roller 15 in an angled relationship to the blades 46, press and hold the leading cut edge of the web W, from which the sheet is being cut against'the surface of the cylinder 16, and thus assist momentarily inforwarding the leading edge of the web.

It will be realized that the cutv trailing edge of the sheet is bowed with respect to thecylinder 16 during the time the cut is being made. This is due to the fact that the knives cut the web from the edges progressively toward the center.

sideframe members 11 and 11', between which are journalled 'resp'ectively the rotatablecutting roller 15 and the rotatable collecting cylinder 16. The shaft 90 of roller 15 carries a gear 89, meshing with a gear 87 fixed to the shaft 88 of cylinder 16, so that these parts rotate in timed relation with one another. The web W which is being handled is directed, by means described in detail in the prior application, so as to pass around the collecting cylinder 16, where it is cut by means to be described, and the cut end at the trailing edge of the cut is forced by the forward face of one of the rotating knives into a The cylinder 16 is provided with three sets of equally spaced grippers 47, and each gripper 47 is positioned approximately radially with respect to the cylinder 16 and no part of said grippers extends beyond the peripheral surface of said cylinder. Each gripper 47 is supported from a shaft 48 that is pivotally mounted on the cylinder 16. Each set of grippers 47 is opened and closed at the proper instant by a lever 52 having a cam roller 50 which is acted upon by a cam 51 supported from the frame 11 by bolts 54. The shape of the cam 51 is such that each set of grippers 47 will be open as they approach the point of cutting. This allows the tucking blade 46 to press the leading edge of the web into the recess 53. The grippers 47, under control of the cam 51, close to press the leading edge of the web against the trailing side of the knife 36.

It should be noted that the bite of the grippers is substantially radially disposed on the cylinder 16, that the grippers grip the paper on the side that is toward the cylinder, and that each gripper is substantially below the surface of the cylinder and therefore underneath the paper. Preferably the grippers will remain closed for the remainder of the revolution of the cylinder 16, opening only at a point just prior to the cutting operation as hereinbefore described.

Inasmuch as the roller 15 and cylinder 16 may be rotating at high speeds, it is important that the cutting edges of knives 35 and 36 accurately engage each other in order to make a perfectly smooth and straight cut, without tearing or mutilating the paper. This requirement would ordinarily necessitate extremely accurate placement of the knives on the respective rotating rollers, and even with this care, any wear or looseness in the parts would contribute to errors in the proper engaging of the knives. The

present invention provides for spring mounting one of the knives of each set, together with a special configuration of the cutting edge of at least one knife, so that proper engagement is automatically achieved even though there may be slight inaccuracies in the placement of the knives on their rollers or cylinders.

Referring to Figs. 4 and of the drawings, the two knives are shown to greater scale, both in elevation and cross-section. Knife 36, in these figures, is one of the straight-edge knives carried by cylinder 16, and it has length, as seen in Fig. 4, which allows its ends to extend past the edges of the web W carried through the machine. The V-shaped knife 35, which is one of those carried by roller 15, also extends beyond the edges of the web being handled. As better shown in Fig. 5, the cutting edge of knife 36 is a simple bevel edge 100, while the cutting edge of knife 35 is formed by a curved edge 102 which, for the major portion of the length of the knife, is of an involute curvature referred to the center of rotation of the roller 15, so that the cutting edges of the two knives remain in engagement during a considerable travel of the rotating parts.

As the knives making up one cooperative pair approach one another. the initial contact between the ends of knife 35 and knife 36 occurs outside the edges of the web. At these ends of knife 35, and as best seen in Fig. 5, the normal involute curvature (indicated by dash line 104) of that edge is modified by rounding off the tips to a smaller radius as indicated by numeral 106.

in operation, the rounded tips 106 provide a clearance for knife 36 as the two knives enter into engagement, and the involute curvature, which comes into effect after the initial engagement, permits the knives to remain in engagement over a range of rotational movement while springs 37 provide firm shearing contact. The extent of the modified or rounded portion at each end of blade 35 is indicated by the are 108 in Fig. 5.

Since the initial engagement of the two knives is accomplished before any of the material of web W is actually cut, it is clear that the knives can adjust themselves to any slight inaccuracy in placement, springs 37 being sufiiciently resilient to allow this adjustment to take place. T hereupon, and as the rotation of the roller and cylinder 16 progresses, edges of the knives continue to approach each other, and actual cutting commences at A about the point at which the cross-sectional form of knife 35becomes a true involute.

I have found that the rounding off of the tips of the edges of one of the two knives is of great importance in assuring that proper engagement of the two knives occurs, since it makes it possible to mount the knives upon their respective rollers or cylinders without the extreme accuracy that would otherwise be required. This is particularly so where, as in the present machine, the knives on one roller coact, at different points in one revolution, with several different knives on the other roller or cylinder.

While, in the structure shown, both of the knives have been shown as rotatably mounted, a similar effect, and attendant advantages, would also be realized if one only of the knives were mounted on a cylinder and the other had straight line motion. Other slight modifications in the structure shown will occur to those skilled in this art, for particular applications, and the invention is therefore not to be taken as limited to the details illustrated herein, except as may be required by the scope of the appended claims.

I claim:

1. A blade adapted for use in web cutting machines having rotary web cutting elements, said blade having a forward end adapted to cooperate with a straight-edge cutting knife, said blade having one major surface flat and its opposite major surface at said forward end of the blade curved on an involute curve towards its flat surface and adapted for engagement with the cutting knife, said end of said blade being formed as a reentrant V with its apex on the longitudinal center-line of the blade, the planes defining said V intersecting said involute surface and being inclined to the plane of said fiat surface to provide an undercut edge where said planes intersect the involute surface, and the blade tips at the side edges of said blade at said end being rounded off, as viewed in side elevation, to a curvature inside the envelope of said involute surface.

2. In a web cutting machine, in combination, a pair of rotatable cylinders, cooperating cutting elements carried by the respective cylinders for engagement thereof together during a portion of their rotative movements, one of said elements being a straight-edged knife and the other being a blade comprising a one-piece structure having one major surface fiat and its opposite major surface at said forward end of the blade curved on an involute curve towards its flat surface and adapted for engagement with the cutting knife, said end of said blade being formed as a reentrant V with its apex on the longitudinal centerline of the blade, the planes defining said V intersecting said involute surface and being inclined to the plane of said flat surface to provide an undercut edge where said planes intersect the involute surface, and the blade tips at the side edges of said blade at said end being rounded off, as viewed in side elevation, to a curvature inside the envelope of said involute surface.

References Cited in the file of this patent UNITED STATES PATENTS 162,607 Biedinger Apr. 27, 1875 1,398,474 Strawn Nov. 29, 1921 2,125,939 Macfarren Aug. 8, 1938' 2,246,957 Shields June 24, 1941