US2757585A - Method and apparatus for removing waste from box blank sheets - Google Patents

Description

2,757,,5 METHOD AND APPARATUS FOR REMOVING WASTE FROM BOX BLANK SHEETS Filed Nov. 5, 1950 F. A. WENZEL.

2 sh'eets sneet l attorneys F- A. WENZEL Aug '7, 1956 METHOD AND APPARATUS FOR REMOVING WASTE FROM BOX BLANK SHEETS Filed NOV. 5, 1950.

2 Sheets-Sheet 2 3rmentor FkEDEmcK A ws/vz E4.

Mud, mfm

Gttornegs United States Patent Frederick A. Wenzel, Milwaukee, Wis., assignor to Cornell Paperboard Products Co., a corporation of Wisconsin Application November 3, 1950, SerialNo. 193,891

4 Claims. (CI. 93-36) This invention relates to a method of removing waste from box blank sheets and a waste knock-out attachment for box blank machines.

In machines for the die cutting of box blanks from cardboard sheets, the dies are usually made to cut a number of blanks from a single sheet. None of the cardboard material of the sheet is ordinarily severed completely, and after the sheets have been deliverd and stacked, an operator using a manual or air-powered chisel cuts away the waste from around the edges of the sheet and from between the individual blanks as defined by the die cut lines which nearly penetrate the sheet.

The present invention deals with the removal of the small areas of the sheet lying between the blanks in the interior of the sheet, these areas being frequently so small and inaccessible as to otter considerable problems where their removal is dependent upon the use of a chisel. Numerous attempts have been made to eliminate such waste mechanically prior to the delivery of the sheet from the die cutting machine, but these have either resulted in damage to the blanks, or have resulted in breaking the blanks out of the sheet, thus increasing the difiiculty of handling the blanks thereafter. The present invention uses an air jet operating in timed synchronism with the delivery of each blank to blow out the waste pieces from the interior of the sheet without requiring any mechanical tool to contact the sheet, and without injury to the blank, and without separation of any individual blank from the sheet as a whole.

The invention is further concerned with the manner in which the air jet Waste eliminating nozzles of my invention are so mounted and operated as to be of universal utility regardless of the sizes and shapes of the box blanks. Not only are the nozzles adjustable from side to side across the path of travel of the sheets delivered by the die cutting machine, and also adjustable vertically respect ing the sheets, but their timing is subject to adjustable control so that the air blast may be set to occur at any desired point or points in the course of sheet travel.

In the drawings:

Fig. 1 is a fragmentary side elevational view of a box Fig. 5 is a view of the cam partially in rear elevation 2,757,585 Patented Aug. 7, 1956 has been removed in accordance with the present invention.

Fig. 8 is a diagrammatic plan view of an arrangement for operating the air blast control valves at individually timed intervals.

The machine for die cutting the sheets to form box blanks therefrom constitutes no part of the present invention, and portions of the machine are illustrated merely to show the application of the waste eliminating means presently to be disclosed.

From a stack of sheets at 10, individual sheets of cardboard or the like are successively delivered by conveyor 11 onto the matrix roll 12, about which the sheets travel to be cut in predetermined patterns by the die 13. This die reciprocates beneath roll 12 to co-act. therewith and to divide the individual sheets 15 in any predetermined path of box blanks as, for example, those shown at 16 in Figs. 6 and 7.

The various flaps and tabs of the box blanks are desirably so designed as to leave a minimum of scrap between them. However, there are in the sheets shown in Fig. 6, small rectangles 17, 18, which are not used in the blanks and constitute waste. Since it is desired that the various sheets may be continued to be handled as such, even after the blanks have been partially severed, the waste cardboard at 17, 18 should be removed to leave the openings and shown in Fig. 7. In such a stack of sheets as that shown at 150 in Fig. 7, it is a matter of consider able expense and difiiculty to eliminate the small pieces of waste. I have succeeded in doing this on the die cutting machine.

As the die cut sheet 15 leaves the matrix roll 12, it is engaged between the upper and lower belts of conveyor 19 which deliver the sheet onto the top of a stack 150. The truing device 20 operated by link 21 from hell crank 22 is used to register each successive sheet at the top of stack 150. The bell crank 22 is operated by the link 23 from the crank arm 24 on shaft 25.

This shaft, which makes one rotation in the course of the delivery of each sheet, is a convenient one upon which to mount the cam disk 26 (Figs. 4 and 5) for the purpose of the present invention. The cam disk has about its periphery a series of holes 27 to receive the screws 28 which adjustably attach to the disk the radially projecting cams 30. Any desired number of cams may be used. Since the particular sheet 15 shown in Figs. 6 and 7 has but three of the small rectangular pieces of waste 17 in any given line in the direction of sheet travel, it is only necessary, for the purposes of this sheet, to employ three of the cams 30.

Attached to a portion 31 of the frame of the machine in proximity to shaft 25 and cam disk 26, is a bracket 32 which adjustably supports near its upper end a switch 33 having a switch actuator 34. Near the lower end of the bracket is a block 35 upon which is mounted a motion transmitting spring 36 having its intermediate portion in the path of movement of the successive earns 30 as they rotate with disk 26 on shaft 25. Thus, in each rotation of shaft 25, the spring 36 will engage the switch actuator 34 to close the switch circuit as many times as there are cams 30 upon disk 36 (three in each instance). The electrical connections 38 controlled by switch 33 are led through suitable conduits 39, 40 to the top of the machine where the wires are operatively connected for the actuation of solenoid valves 41 controlling the delivery of air through branch pipes 42 from the air supply means 43.

The air supply means 43 may conveniently be carried by brackets 44, 45 from the sides of the machine as best shown in Fig. 3, and it may be used to carry a bar 46 upon which the clamps 47 are adjustable laterally of the machine, being anchored in any desired adjustment along the bar by their respective set screws 48 (Figs. 2 and 3).

Projecting forwardly beneath the pipe 43 from each of the clamps 47 is a rod 49 for the adjustable support of the air jet nozzle 50. Each nozzle is connected by a flexible hose 51 with one of the branch pipes 42 controlled by a solenoid valve. Thus, each time one of the earns 30 on shaft 23 closes the switch 33, the solenoid valves will admit air under pressure to the respective nozzles, thus instantaneously creating a blast downwardly in the direction of the sheet passing beneath the nozzles. By adjustment of the cams 30, it is possible to time this blast to occur in accurate synchronism with the passage beneath the ring nozzles of the small pieces of waste 17 which are to be removed. The location of the individual nozzles may also be adjusted both laterally and longitudinally so that the nozzles will accurately register with the waste at the time the blast occurs. The air may be under any desired pressure suflicient to make the blast eiiective. I

have found that in actual practice, air at a pressure of I 80 pounds per square inch is adequate to blow out the waste pieces .17 as shown in Fig. 3, thereby leaving open the holes 170 without otherwise disrupting the sheet 15.

A pan shown at 53 in Fig. 1 is located directly beneath the conveyor 19 to receive the Waste pieces 17 and 18. The pan is disposed at an angle as shown, to guide the waste pieces for collection.

If desired, the air blast nozzles may be selectively operated in any sequence by providing each solenoid valve with an individual control switch 33 and operating each switch with a separate cam on shaft 25 as shown diagrammatically in Fig. 8.

Since, in the particular sheets herein disclosed, it is desired not to separate the individual blanks, I make no eifort, in the presently disclosed device, to remove the waste stock around the edges of the sheets as shown at 52 in Figs. 6 and 7. This stock, all of which is readily accessible, may readily be removed by hand in the conventional way. The hand labor required for removing the stock at the outer edge of the sheet is less than that which would be required to handle the sheets if such waste were removed. However, by removing in the machine the waste stock from the intermediate or central areas of each successive sheet, I have more than half ofthe labor heretofore required in the making of box blanks.

While my improved method will be apparent from the foregoing disclosure, it may be summarized as comprising the following steps:

17 The die cutting of a sheet for the partial severance within the edges of the sheet of box blanks and intervening waste areas.

2. Directing intermittently operable air blasts at the waste areas of the sheet to complete the severance of such areas from the sheet and to dislodge the severedwaste and discharge it from the sheet.

3. The alignment of successive sheets with other sheets using the unimpaired edges of the sheets, and

4. The severance of waste, if any, from the edges of stacked sheets.

More. generically, the. invention consists in the partial severance by a die cutting operation of waste areasv from the. center of the sheet, and the dislodgement and removal of the waste by directing an air blast at the waste in the course of sheet delivery from the die cutting operation.

I claim:

1. A method of cutting a plurality of box blanks, from a sheet of board and removing internal waste from between the blanks, which method comprises the steps of die cutting the sheet upon the outlines of the desired box blanks Within the boundaries of the sheet to define the individual blanks and internal waste by die cut lines which at least nearly penetrate the sheet on said outlines for at least partial severance of the blanks and internal waste pieces spaced within the sheet, completely dislodging internal waste pieces solely by intermittently directing pneumatic blasts substantially only against such internal waste pieces while effecting relative movement between the sheet. and said blasts, and substantially cutting off the blasts between internal waste pieces whereby the margins of the sheet are left intact with the box blanks remaining in assembly therein.

2. The method recited in claim 1 in which the sheet is advanced past successive pneumatic blasts in the direction in which waste pieces are spaced in the sheet, said blasts being intermittently timed in synchronism with sheet advance.

3. An attachment for a machine which cuts box blanks and intervening waste from a sheet of paper board by die cutting at least nearly through the sheet on the outline of the box blank and waste, such attachment comprising means for advancing successive sheets unitarily containing such box blanks and waste, and means for completely dislodging all waste from the sheet without displacing the sheet margins 01' the, box blanks therein, said last mentioned means comprising solely a pneumatic nozzle directed toward the path of sheet advance in alignment with the waste therein, high pressure pneumatic connections for said nozzle, and valve means controlling said connections and provided with means for actuating said valve means in synchronism with sheet advance upon registry of each piece of waste with the nozzle to blast the waste from the sheet, each successive blast from the nozzle being directed substantially only against a piece of waste independently of the rest of the sheet to leave the box blanks and the margins of the sheet. intact while completely removing the internal waste.

4. The device of claim 3 in further combination with sheet. aligning means acting uponv the. intact margins of successive sheets from which internal waste pieces have been wholly removed by said blast for the accurate stacking of successive sheets.

References Cited in the file of this. patent UNITED STATES PATENTS 640,878 Curley Jan. 9, 1900 865,523 Peters Sept. 10, 1907 932,738 Wilson Aug. 31, 1909 1,117,738 Winton Nov. 17, 191.4 1,644,226 Bedard Oct. 4, 1927 1,732,683 Hubl W--. Oct. 22, 1929 1,820,619 Hubl, Aug. 25', 19.31 1,856,832 Halvorson. May 3, 1932 1,914,405 Cummings. lune 20, 1933 1,981,974 Vernimb Nov. 27, 1934 1,983,708 Ruble et a1. v e Dec. 11, 1934 1,987,224 Bergstein Ian. 8, 1935 2,011,585 Lippincott -2 Aug. 20, 1935 2,032,746, Grant Mar. 3, 1.936 2,035,857 Adsit Mar. 31,. 1936 2,073,320 Smith v Mar. 9., 1937 2,193,412 Southarn Mar. 12, 1940 2,298,890 Leonard Oct. 13, 1942 2,359,059 Somes, Sept. 26,, 1944 2,547,884 Pa-asche Apr. 3,, 1951 2,548,370 Hedstrom Apr. 10, 1951 2,561,348 Du-nham s..-. r July 24, 1951 2,577,424 Luehrs. Dec. 4,, 1951 2,655,841 Anness Oct. 20, 1953

Images