Trim ejector for ejecting the trim produced by a rule of a rotary steel rule die apparatus or the like

A trim ejector for ejecting the trim produced by a steel rule of a rotary steel rule die apparatus includes a die cylinder having a die board provided with the rule and an anvil roll positioned parallel to the die cylinder to define a sheet receiving gap therebetween. The trim ejector has a flexible body defining a trim-ejecting surface extending between an ejecting edge and a stem portion, an anchor portion connected to the stem portion of the flexible body for securing the flexible body to the die board to position the ejecting edge of the flexible body adjacent and parallel to the rule, and a compressible biasing member secured to the flexible body on a side opposite the trim-ejecting surface. The compressible biasing member forces the flexible body to a neutral position, corresponding to no tension being applied to the stem portion, when the flexible body is moved away from the neutral position under passage of a sheet in a sheet receiving gap.

FIELD

The present invention relates to paperboard die-cutting. More specifically, the present invention relates to a trim ejector for ejecting the trim produced by a rule of a rotary steel rule die apparatus or the like.

BACKGROUND

The use of a rotary steel rule die apparatus for paperboard die-cutting is well-known. Such apparatus comprises a die cylinder, having a die board, and an anvil roll positioned parallel to the die cylinder so as to define a sheet receiving gap therebetween. The die board is provided with steel rules so mounted to the board in a press-fitted way as to yield a predetermined shape to the sheet to cut, which can be a corrugated board or other sheet materials. The assembly of rules which yields the predetermined shape cut in the sheet will be referred to herein as the die cutting pattern or matrix.

It is a common practice in the field of steel rule die cutting to provide a width of about ½″ (1.27 cm) of extra sheet beyond the rules on all sides except on the front side where an extra width of about ¼″ (0.63 cm) is provided. This extra width is provided to prevent centering problem of the sheet, and to help ejecting the trim.

Currently in the paperboard die-cutting industry, a major part of the waste in the die-cutting operation of corrugated carton relates to the trim around the carton's pattern.

A rotary steel rule die apparatus which would allow minimizing the trim around the carton's pattern is thus desirable.

DETAILED DESCRIPTION

In accordance with a first aspect of the present invention, there is provided a trim ejector for ejecting the trim produced by a rule of a rotary steel rule die apparatus, the rotary steel rule die apparatus further comprising a die cylinder including a die board provided with the rule and an anvil roll positioned parallel to the die cylinder so as to define a sheet receiving gap therebetween, the trim ejector comprising:

a leaf-like body defining a trim-ejecting surface extending between an ejecting edge and a stem portion;

an anchor portion connected to the stem portion of the leaf-like body for securing the leaf-like body to the die board so that the ejecting edge of the leaf-like body is positioned adjacent the rule parallel therefrom; and

a compressible biasing member secured to the leaf-like body on a side thereof opposite the trim-ejecting surface; the compressible biasing member being for forcing the leaf-like body to a neutral position, corresponding to no tension being applied to the stem portion, when the leaf-like member is moved away from the neutral position by a sheet in the sheet receiving gap;

whereby, in operation, when the sheet in the sheet receiving gap causes the rule to cut a trim from the sheet, the sheet exerts the tension on the stem portion and the biasing member is compressed; when the sheet exits the sheet receiving gap, the tension on the stem portion is released and the compressible biasing member forces the leaf-like body to its neutral position which then pushes onto the trim and causes an ejection of the trim.

According to a second aspect of the present invention, there is provided a rotary steel rule die apparatus comprising:

a die cylinder rotatably mounted to a frame including a die board provided with a plurality of steel rules mounted to the die board so as to define a die cutting tool;

an anvil roll mounted to the frame so as to be positioned parallel to the die cylinder and so as to define a sheet receiving gap therebetween; each of the plurality of steel rules producing a respective trim following a passage of a sheet in the sheet receiving gap;

the improvement wherein the apparatus further comprising:

at least one trim ejector mounted to the die board adjacent one of the plurality of steel rules for ejecting the respective trim produced by the one of the plurality of steel rules, the trim ejector comprising:

a leaf-like body defining a trim-ejecting surface extending between an ejecting edge and a stem portion;

an anchor portion connected to the stem portion of the leaf-like body secured the leaf-like body to the die board so that the ejecting edge of the leaf-like body is positioned adjacent the one of the plurality of steel rules generally parallel therefrom; and

a compressible biasing member secured to the leaf-like body on a side thereof opposite the trim-ejecting surface; the compressible biasing member being for forcing the leaf-like body to a neutral position corresponding to no tension being applied to the stem portion, when the leaf-like member is moved away from the neutral position by a sheet in the sheet receiving gap;

whereby, in operation, when the sheet in the sheet receiving gap causes the rule to cut a trim from the sheet, the sheet exerts the tension on the stem portion and the biasing member is compressed; when the sheet exits the sheet receiving gap, the tension on the stem portion is released and the compressible biasing member forces the leaf-like body to its neutral position which then pushes onto the trim and causes an ejection of the trim.

It has been found that the use of a trim ejector according to the present invention allows yielding an extra width of only about ⅛″ (3.2 mm) on the sheet beyond the rules for example. This results in important carton savings.

The trim ejector according to the present invention provides a relatively powerful and fast ejection of the trim around the pattern defined by the rules, which minimizes the bringing of trim and carton's waste in the subsequent cuttings.

According to a third aspect of the present invention, there is provided an ejector for ejecting a sheet in a rotary steel rule die apparatus, the rotary steel rule die apparatus further comprising a die cylinder including a die board provided with a matrix of steel rules and an anvil roll positioned parallel to the die cylinder so as to define a sheet receiving gap therebetween, the ejector comprising:

a leaf-like body defining a sheet-ejecting surface extending between an ejecting edge and a stem portion;

an anchor portion connected to the stem portion of the leaf-like body for securing the leaf-like body to the die board so that the ejecting edge of the leaf-like body is positioned adjacent the rule generally parallel therefrom; and

a compressible biasing member secured to the leaf-like body on a side thereof opposite the sheet-ejecting surface; the compressible biasing member being for forcing the leaf-like body to a neutral position corresponding to no tension being applied to the stem portion, when the leaf-like member is moved away from the neutral position by a sheet in the sheet receiving gap;

whereby, in operation, when the sheet is in the sheet receiving gap, the sheet exerts the tension on the stem portion and the biasing member is compressed; when the sheet exits the sheet receiving gap, the tension on the stem portion is released and the compressible biasing member forces the leaf-like body to its neutral position which then pushes onto the sheet and causes an ejection of the sheet.

Other objects, advantages and features of the present invention will become more apparent upon reading the following non restrictive description of illustrated embodiments thereof, given by way of example only with reference to the accompanying drawings.

Turning now toFIGS. 1 to 3, a trim ejector10for ejecting the trim11produced by a rule12of a rotary steel rule die apparatus14according to a first illustrative embodiment of the present invention will now be described.

As it is well-known, the rotary steel rule die apparatus14comprises a die cylinder16including a die board18and an anvil roll20positioned parallel to the die cylinder16so as to define a sheet-receiving gap22therebetween.

As it is conventionally known, the rules12(four (4) illustrated) are press-fitted to the die board18. As illustrated inFIG. 4, for example, each rule12has center bevel tip24. According to the illustrated example ofFIG. 1, the four rules12are so mounted to the die board18as to define a rectangle pattern25.

As will become more apparent upon reading the following description, trim ejectors10according to the present invention can be used to eject the trims resulting from a different number of rules positioned according to other patterns (not illustrated).

The die cylinder16is conventionally hollow and made of steel or of another heavy duty material. The anvil roll20is also a hollow cylinder conventionally provided with a polyurethane coating. Both rolls are rotatably mounted to a frame26. The rotation of the die cylinder16is actuated by a drive assembly (not shown).

The die board18is mounted to the die cylinder via fasteners (not shown). The board is made for example of arcuate shaped plywood. It can also be made of other material, such as paper based board and polymeric material for example.

The rotary steel rule die apparatus14further includes a plurality of rubber blocks26. The rubber blocks26are provided to suspend and eject the blank resulting from the cut of the sheet28within the rectangle pattern25and therefore ease its removal by gravity. The rubber blocks26are of course not limited to this material.

The rotary steel rule die apparatus14further includes a plurality of trim cutters30extending from the rules12perpendicularly therefrom outside from the rectangle25. As it is also believed to be well-known in the art, the trim-cutters30are provided to cut the trim11on each side of the rectangle25in a plurality of pieces (four (4) according to the illustrated embodiment) so as to facilitate its ejection.

Since the configuration and general operation of a rotary steel rule die apparatus14is believed to be well-known in the art, and for concision purposes, they will not be described furtherin.

The apparatus14further comprises a plurality of trim ejectors10for ejecting the trim11produced by each rule12. As can be seen onFIG. 1, the trim ejectors10are mounted to the die board18in pair so as to provide a trim ejector10from each pair on a respective side of each trim-cutter30. This arrangement has been found to increase the ejection efficiency when trim-cutters30are used.

The present invention is not limited to the arrangement and positioning of the trim ejectors10illustrated inFIG. 1. For example, trim ejectors10can be mounted to the board18on the periphery of the rectangle25outside thereof or of any other shape formed by the rules12to eject the trim produced thereby without requiring the use of trim-cutters30.

Turning now toFIGS. 2 and 3, one of the identical trim ejectors10will now be described in more detail.

The trim ejector10comprises a leaf-like body32defining a trim-ejecting surface34extending between an ejecting edge36and a stem portion38, an anchor portion40integrally connected to the stem portion38and a compressible biasing member42secured to the leaf-like body32adjacent the ejecting edge36.

The leaf-like body32and the anchor portion40are integral and are made of UHMW plastic. Any other polymeric or resistant and flexible material can also be used. Any material which prevents sticking of the trim to the leaf-like body32is preferably used. According to another embodiment (not shown), the leaf-like body32and the anchor portion40are made of two individual parts which are assembled using glue or any other fastening means. They can also be configured so as to be snap-fitted for example.

The anchor portion40renders the installation of the trim ejectors10rapid and straight forward.

The leaf-like body32includes a U-shape portion44defined by a free leg46and an attached leg50, mounting the U-shape portion44to the rest of the leaf-like body32. The upper portion of the free leg46includes the afore-mentioned ejecting edge36. The free leg46of the U-shape portion44further includes a fold-back48which extends in the plane defined by the trim-ejecting surface34towards the attached leg50of the U-shape portion44so as to partially close the gap52between the two legs46and50.

As will be described furtherin with reference toFIGS. 4 to 7, the U-shape portion44of the body32allows the ejecting edge36to act as a wiper blade during operation of the trim ejector10. The U-shape portion44of the body32allows the ejecting edge36to remain in contact with the steel rule12(seeFIG. 4for example) throughout the sequential cutting and trim ejecting operations. This contributes to minimizing the jamming of trims between the ejector10and the rule12.

The leaf-like body32is configured so that the maximum vertical course of the edge36is ¼″ (6.3 mm) and its maximum horizontal course is 3/16″ (4.76 mm). The clearance angle of the edge36, which remains substantially constant throughout the operation, is between about three (3) to twenty (20) degrees.

These operational characteristics of the leaf-like body32and more specifically of its edge36are provided only as an example. It is believed to be within the reach of a person skilled in the art to adapt the present teaching for another application or for a specific type of sheet and to modify the configuration of the U-shape portion44to yield other clearance and maximum courses therefore.

The anchor portion40is in the form of a flat base integrally connected to the leaf-like portion32via the stem portion38. The stem portion38extends at an angle of about 20 degrees at a position corresponding of about two third from the edge of the anchor portion40.

The trim ejector10is mounted to the die board18using an adhesive such as glue or fasteners. It is so positioned relatively to the rule12so that the ejecting edge36is parallel thereto. More specifically, the free leg46of the U-shape portion44is so positioned relatively to the rule12when no tension is applied to the stem portion38that the free leg46abuts the rule12. The trim ejector is so configured and sized that, in such a neutral position, which is illustrated inFIG. 4, the ejecting edge36extends further the rule12relatively to the board18.

The U-shape portion44contributes to the free legs46remaining in contact with the rule12during operation of the ejector10and the ejecting edge36acting as a scraper blade along the rule12as will be explained hereinbelow in more detail.

The trim ejector10further comprises a compressible biasing member42secured to the leaf-like body32adjacent the U-shape portion44. The biasing member42is made of polyurethane foam and extends substantially throughout the width of the leaf-like body32. Other elastomeric material can be used to make the biasing member, including without limitations neoprene foam and pure gum rubber to name a few.

As can be better seen fromFIG. 3, the biasing member42is dimensioned so that its bottom surface54is leveled with the bottom surface56of the anchor portion40so that the biasing member contacts the die board18when the ejector10is secure to the board18via its anchor portion40.

To simplify the mounting of the trim ejector10to the board18, the biasing element42is not secured to the board18. However, the biasing member42and leaf-like body42are configured so that the biasing member is complementary engaged in a recess58formed in the leaf-like body32under the trim-ejecting surface34, adjacent the U-shape portion44. The biasing member42includes a complementary portion in the form of a lip60. The biasing member is further glued to the leaf-like body32.

The compressible biasing member42is provided between the leaf-like body32and the die-board18for forcing the leaf-like body32to a neutral position, which corresponds to no tension being applied to the stem portion38, when the leaf-like member32is moved away from the neutral position under the passage of a sheet28in the sheet receiving gap22as will be described hereinbelow in more detail.

The biasing member42is made of a compressible material allowing the biasing member to act as a compression spring which provides a biasing force sufficient to eject the trim11and greater than the friction of the free leg46onto the rule12. This last force creates a scraping effect of the leg46onto the rule12and thereby helps preventing accumulation of cuttings between the rule12and the leg46. To summarize, the biasing force should be sufficient to overcome the scraping force and to eject the trim.

The operation of the trim ejector10will now be described in more detail with reference toFIGS. 4 to 7.

As can be seen inFIG. 4, a corrugated sheet28or another sheet which is fed to the apparatus14by the two rolls16and20enters the sheet-receiving gap22(see arrow62) until the gap22. As it is well-known in the art, the feeding of the sheet28is synchronized with the rotation of the die cylinder16.

During this stage, no force is applied onto the stem portion38of the ejector10which is still in a neutral position. It is also to be noted that the ejecting edge36extends further than the rule12when the ejector is in its neutral position.

FIG. 5illustrates the trim ejector10just before the beginning of the cutting of the trim by the rule12. At this stage, the tightness of the gap22forces the sheet28to push onto the trim ejector10towards the die board18and therefore to compress the biasing member42(see arrow64). The ejecting edge36is then pushed beyond the edge of the rule12. The U-shape portion44bends and the free legs thereof46remains firmly applied onto the rule12.

FIG. 6illustrates the sheet28reaching a point between the two rolls16and20where the illustrated portion of the sheet28is cut by the rule12. The resulting trim11is further simultaneously cut in pieces by the trim cutters30(only one shown inFIG. 6).

As illustrated inFIG. 6, the biasing member42is then fully compressed by the force applied by the sheet28onto the leaf-like portion32of the trim ejector10. A tension is also exerted onto the stem portion38of the ejector10.

FIG. 7shows the beginning of the exit of the sheet28(see arrow66).

Since an external force is no longer applied onto the trim ejector10, the compressed biasing member42pushes back the leaf-like body32into its neutral position (see arrow68) which in turn ejects the trim11out of the gap22(see arrow70).

As previously noted, the U-shape portion44exerts a force on its free leg46throughout the operation, yielding a scraping effect onto the rule12.

The trim ejector10has been found to be both tear and fatigue resistant. The ejector10has also been found to be reliable to over 500 000 cycles.

The biasing member42can take other form allowing forcing the leaf-like body32to a neutral position, corresponding to no tension being applied to the stem portion38, when the leaf-like member32is moved away from the neutral position under a passage of a sheet28in the sheet receiving gap. Also, the leaf-like body32and the biasing member42can be configured differently to allow attachment of the biasing member42to the leaf-like body32.

Even though the trim ejector10has been illustrated mounted adjacent a center bevel rule, it can be used also along a side bevel rule.

Turning now toFIG. 8of the appended drawings, a trim ejector72according to a second illustrated embodiment of the present invention will now be described. Since the trim ejector72is similar to the trim ejector10, and for concision purposes, only the differences between these two embodiments will be described herein.

The trim ejector72comprises an S-shape leaf-like body74, defining a trim-ejecting surface extending between an ejecting edge76and a stem portion78, an anchor portion80integrally connected to the stem portion78and a compressible biasing member82secured to the leaf-like body32on a side thereof opposite the trim-ejecting surface adjacent the stem portion78.

Similarly to the leaf-like body32, the leaf-like body74includes a fold-back84extending from the ejecting edge76away therefrom so as to define an extension to the trim-ejecting surface. The overall shape of the leaf-like body74aims at increasing its flexibility to maximize the course of the ejecting edge76and thereby add to the trim ejecting efficiency.

The anchor portion80is longer than the anchor portion40of the trim ejector72. The extra length of the base towards the ejecting edge76aims at compensating for the positioning of the biasing member82adjacent the stem portion78.

The biasing member82is therefore secured to the leaf-like body74between the body74and the anchor portion80. It includes a slanted side86opposite the stem portion78which provides a greater clearance for the mobile portion of the leaf-like body74.

The trim ejector72is positioned relatively to the rule12by abutting the proximate end88of the anchor portion with the rule12.

In operation, the trim ejector72acts similarly to the trim ejector10with the difference that the scraping effect provided by the U-shaped portion44in the case of the ejector10is provided by the S-shape of the leaf-like body74in the case of the trim ejector72.

A trim ejector90according to a third illustrated embodiment of the present invention will now be described with reference toFIG. 9. Since the trim ejector90is similar to the trim ejector10, and for concision purposes, only the differences between these two embodiments will be described herein.

The trim ejector90comprises a leaf-like body92, defining a trim-ejecting surface94extending between an ejecting end portion96and an S-shape stem portion98, an anchor portion100integrally connected to the stem portion98and a compressible biasing member102secured to the leaf-like body92on a side thereof opposite the trim-ejecting surface94.

The S-shape of the stem portion98allows minimizing the stress of the leaf-like body92considering its overall shape.

The ejecting end portion96is in the form of a fork having a top leg104defining an extension of the trim-ejecting surface94and a bottom leg106biased from the top leg and defining a mechanical stop to limit the course of the of the leaf-like body92towards the die board18(not shown inFIG. 9).

The biasing member102is shaped to complement the contour of the inner leaf-like body92and is sized so as to contact the die board18.

Turning now toFIG. 10of the appended drawings, a trim ejector108according to a fourth illustrated embodiment of the present invention will now be described. Since the trim ejector108is similar to the trim ejector10, and for concision purposes, only the differences between these two embodiments will be described herein.

The trim ejector108is a one-piece ramp-shape body comprising a leaf-like portion110, defining a trim-ejecting surface extending between an ejecting edge112and a stem portion114, an anchor portion116integrally connected to the stem portion116and a compressible biasing member118is in the form of an arcuate segment secured to both the leaf-like portion10and to the anchor portion116therebetween.

The ejecting edge112is defined by a lip, which extends at the end of the leaf-like portion110opposite the stem portion114and which is intended to lie over the cutting edge of the rule12before the first impression. After a first pass, the excess is eliminated and the lip112becomes flush with the cutting bevel creating the scraping effect on the cutting rule12.

The leaf-like portion110further includes a retention protrusion120, extending along the width of the device108on the ramp adjacent the rule12, to retain the material in position prior to cutting.

The leaf-like portion110, anchor portion116and the biasing element118together define a below122that creates suction and air movement within the device on each cycle. This below can help eliminate dust and small particles of material that may accumulate in some applications.

Even though the ejectors10,72,90and108have been illustrated to eject the trim11resulting from the cutting of the sheet28, their functionalities are not limited to such an application. Positioned within perimeter defined by the rectangle formed by the rules12, the ejectors (not shown) can be used for example to replace the blocks26to help eject the sheet28after the die-cutting process. Such use of the ejectors can be in addition or alternatively to the use of further trim ejectors as described hereinabove.

Even though the trim ejectors10,72,90and108have all been illustrated so mounted to the die board relative to the rule that their respective ejecting edge abuts the rule while the trim ejector is in a neutral position so as to provide a scrapping effect during operation, a trim ejector according to the present invention can also be mounted to the die board so as to be positioned adjacent a rule without contacting it. Even though in such a case the above-mentioned scraping effect will be absent, the trim ejecting effect will still be present.

The width of a trim ejector according to the present invention may of course vary.

A trim ejector according to the present invention is not limited to having a compressible biasing member made of foam of an elastomeric material. It can be made for example of metal. A conventional coil spring can be sued for example.

Also, even though trim ejectors according to the present invention have been illustrated as being made partly of polymeric and/or elastomeric materials, they can also be made completely or partly of metal.

Although the present invention has been described hereinabove by way of illustrated embodiments thereof, it can be modified, without departing from the spirit and nature of the subject invention as defined in the appended claims.