Self-combing pin type stripper for blank-forming apparatus

March 5, 1968 _P. zernov 3,371,584

SELF-COMBING FIN TYPE STRIPPER FOR BLANK-FORMING APPARATUS Filed July 8, 1966

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INVENTOR;

PETER ZERNOV

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United States Patent Office

3,371,584

Patented Mar. 5, 1968

3,371,584 SELF-COMBING PIN TYPE STRIPPER FOR BLANK-FORMING APPARATUS

Peter Zernov, Milwaukee, Wis., assignor to Zerand Corporation, Menomonee Falls, Wis., a corporation of Wisconsin

Filed July 8,1966, Ser. No. 563,797

Claims. (Cl. 93—36)

The present invention relates generally to apparatus for forming carton blanks or the like, and more particularly relates to the stripping mechanism for stripping the waste or scrap portion from the cut and/or scored blank.

This application is an improvement over my copending application Ser. No. 407,817 filed October 30, 1964, now Patent No. 3,320,864, entitled, “Self-Combing Pin Type Stripper for Blank-Forming Apparatus.”

The present invention relates to an improved pin type stripper mechanism for blank forming apparatus, which mechanism provides pins that are radially fixed on rotatable cylinder so as to accommodate any blank configuration, without regard to a pin combing device, and therefor provides complete flexibility in the location of the pins around the periphery of the drum.

In the pin stripper mechanism of said copending application, the pins were forceably retracted by an ejector cylinder which pushed against the pointed ends of the pins so as to force them into the drum on which they were mounted. While this device did work satisfactorily, the sharpened ends of the pins in time became dull due to the action of the ejector cylinder. Also in the device of said copending application, it was necessary to also have a brush roll cylinder for cleaning the scrap positively from the pins.

In accordance with the present invention, an improved stripper pin assembly is provided in which the pin is radially fixed in the drum and instead a sleeve is mounted around the pin for sliding relative thereto. Thus when the stripping action of the scrap material from the pin is to be accomplished, the slidable sleeve is forced radially outward in respect to and over the sharpened end of the stripper pin, thus forceably ejecting the scrap material from its impalement on the pin. With the present arrangement, it is unnecessary for the pin itself to be shifted back within its mounting drum, and the ejector cylinder and brush roll have been eliminated. Furthermore, substantially greater pin life has been obtained than with conventional stripper pins, and down time for these machines has been substantially reduced because it is unnecessary to replace or repair the pins at frequent intervals.

These and other objects and advantages of the present invention will appear hereinafter as this disclosure progresses, reference being had to the accompanying drawings in which:

FIGURE 1 is a side elevational view in section of a blank forming apparatus embodying the present invention, certain parts being removed or broken away for the sake of clarity;

FIGURE 2 is a fragmentary, enlarged view of a portion of the pin stripper mechanism shown in FIGURE 1; and

FIGURE 3 is a fragmentary, enlarged detail view of a portion of the device shown in FIGURE 2, but showing the ejector sleeve shifted to the radially outward position.

The general organization of the present apparatus includes the stripper drum assembly 3 and an upper anvil roll 4. The blank B and scrap portion S travel in the direction indicated by the arrow and between the stripper cylinder and the anvil roll, and are guided in their movement between these rolls by the stiff riders 6 which ex10 tend therebetween. It is while passing between stripper cylinder and the anvil roll that the scrap is impaled on the stripper pins 7. The scrap material then travels on the pin until stripped off by means to be described.

Referring now in greater detail to the drawings, a stripper assembly includes a hollow cylinder 10 having a plurality of openings around its periphery and also in axially spaced relationship. Each of the internally threaded openings 11 has a counterbore 12 at its outer end and a bushing 13 is threadably engaged in the openings 11. These bushings have means on their outer ends, such as a hexagonal shape, by which they are tightly engaged by a wrench into the drum 10. A washer 14 is press fit into the counterbore 12 and serves to prevent the underside of the hex portion of the bushing from marring the relatively soft drum 10. To assemble the unit, the washer 14 has internal threads by means of which it is threadably engaged on the bushing before being inserted in the counterbores of the drums. When the washer is in place on the bushing, the bushing is free to turn in the washer because of the necked down portion 15 of the bushing.

The bushing has an internal diameter 16 in which is slidably mounted an ejector sleeve 17. Means are provided for fixing the pin in the bushing, and this means takes the form of a pin 18 which extends through slots 20 in opposite sides of the sleeve. Thus the sleeve can slide back and forth relative to and over the pin, and from the retracted position shown in FIGURE 2 to the ejecting position shown in FIGURE 3.

It will be noted that the diameter of the head Ία of the pin is considerably smaller than the body portion 7Z&gt; of the pin. This prevents the frayed portion 21 of the blank scrap S from interfering with the return movement of the sleeve inwardly of the bushing.

A back up cylinder 22 is rotatably and eccentrically mounted within the cylinder 10, as clearly shown in FIGURE 1. If a more complete description of the means for mounting these cylinders is deemed to be either necessary or desirable, reference may be had to my said copending application Ser. No. 407,817.

As shown in FIGURE 1, when the pin assembly is located adjacent the anvil roll 4, the eccentricity between the back up cylinder 22 and the outer drum 10 is greatest, which permits the slidable sleeve 17 to be positioned in its innermost position, thus exposing the pin head Ία for impaling the blank scrap S. As the cylinder 10 rotates in the direction of the curvilinear arrow, the eccentricity between the back up cylinder and the outer drum decreases, thus causing the slidable sleeve to be positively shifted in a radially outward direction and over the pin head, to a position shown at the lower side of the drum of FIGURE 1. In so shifting in an outer direction, this sleeve forceably pushes the scrap portion S from the impaled position on the pin head, thus freeing the scrap portion and permitting it to drop freely from the pin. As the drum continues to rotate the eccentricity between the central back up cylinder and the drum increases, thus providing sufficient clearance for the sleeve to move radially inwardly by bearing against the blank, and again exposing the pin head for the next impalement of the scrap portion. It will be noted that the pin remains radially fixed in the cylinder while its surrounding sleeve shifts radially in respect thereto. The. sleeve contacts the impaled scrap portion and forceably ejects it from the pin, there being no necessity to contact the sharpened end of the pin to retract it.

By means of the present invention, a pin assembly has been provided which seldom needs sharpening or repair, and the apparatus requires no ejector cylinder or brush roll for aiding in the removal of the scrap portions.

By providing clearance between the pin head Ία and the bore 23 of the slidable sleeve, the formation of loose

3.371.584 ³ rings of scrap material by the shearing action is prevented, the pin is kept free of the scrap material, and smooth working of all the parts is assured.

Various modes of carrying out the invention are contemplated as being within the scope of the following 5 claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention.