US 3780929 A
A corner post construction and a method of making same wherein an L-shaped post has a plurality of corrugated board plies adhesively secured together in a stack of such plies superimposed with respect to each other with one group of the stack being narrower than the other portion. A hinge connects the bottom narrower ply and top wider ply at a common edge. The abrasive inside edges of the narrower group of plies is coated with a soft, non-abrasive material to reduce the abrasive nature of the edge and to seal sawdust and dirt into the corner post edge. Other edges and surfaces which may contact articles within a package can also be coated.
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Description (OCR text may contain errors)
United States Patent [1 1 Terrasi PACKAGING CONSTRUCTION  Inventor: Chris C. Terrasi, Grand Rapids,
 Assignee: Stack-Pac Corporation, Grand Rapids, Mich.
221 Filed: June 11, 1971 21 Appl. No.: 152,226
[451 Dec. 25, 1973 FOREIGN PATENTS OR APPLICATIONS 420,980 3/1967 Switzerland 229/14 C Primary Examiner-Leonard Summer Attomey-John E. McCarty [5 7] ABSTRACT A comer post construction and a method of making same wherein an L-shaped post has a plurality of corrugated board plies adhesively secured together in a stack of such plies superimposed with respect to each other with one group of the stack being narrower than the other portion. A hinge connects the bottom narrower ply and top wider ply at a common edge. The abrasive inside edges of the narrower group of plies is coated with a soft, non-abrasive material to reduce the abrasive nature of the edge and to seal sawdust and dirt into the corner post edge. Other edges and surfaces which may contact articles within a package can also be coated.
3 Claims, 3 Drawing Figures PACKAGING CONSTRUCTION BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to corner posts. In one of its aspects, the invention relates to an L-shaped corner post formed from a uniform thickness stack of ply members. In another of its aspects, the invention relates to a corner post whose cut abrasive edges are coated with a soft, non-abrasive material which seals dirt and sawdust into the corner post. i
2. State of the Prior Art Corner posts are well known in the packaging art. They are used predominantly in cartons between the carton wall, mostly in corners, and the article to be packaged in the carton to protect the articles from damage in transit.
A well known type of corner post is a buildup" in which a plurality of corrugated board plies are adhesively secured totether. In some instances, kerfs have been cut into a stack of plies. One portion of the stack is then folded 90 with respect to another portion of the stack to form an L-shaped corner post. In most cases, the posts are formed with the plies of one leg perpendicular to the plies of the other leg so that the cut edges do not come in contact with the product. The cut edges of the corrugated board plies are abrasive to the articles within the package. Many ingenious but expensive forming operations have been devised for making such corner posts so that the cut edges of the corner posts avoid contact with the package. For example, see US. Pat. No. 3,337,] 1 1 to Petriekis et al. In these types of corner posts, the starting shapes must be made from special configurations of plies, i.e., where the stack of plies is of a nonuniform thickness because certain of the ply are of a different shape. This construction requires special cutting, gluing and folding operations which do not necessarily lend themselves to automated operations. Thus, the cost of producing these corner posts is substantial because of the hand labor involved and the specialized operations.
In some corner post constructions, the outer surfaces of the paperboard or corrugated board ply have been coated with wax or plastic prior to forming the corner posts. Such coatings have not covered the cut edges of the corner posts and the resulting corner post is still quite abrasive at the cut edges. Further, the sawing operation by which the corner posts are made produces sawdust at the cut edges, making the corner post somewhat dirty. The result of these corner posts is that the product becomes dirty in transit from the corner posts. Heretofore, no solution has been proposed for inexpensively and simply manufacturing corner posts wherein the product is protected from the cut abrasive edges of the corner posts.
BRIEF STATEMENT OF THE INVENTION I have now discovered a simple and inexpensive corner post which can be easily and quickly manufactured at a minimum cost and from standard easily prepared material, the corner post having edges and surfaces which are nonabrasive. Briefly, the corner post of the invention is formed by cutting a slot in a uniform thickness stack of ply members of a flat stiff sheet material, leaving a hinge between a narrow and wide portion of the stack, and then folding the portions together on the hinge so that an L-shaped corner post is formed with adhesive between the folded portions. A soft protective coating is then applied, preferably by spraying, to the cut surfaces which will contact the product. The corner post thus formed has a wide base of a plurality of ply members of a stiff sheet material adhesively secured together, and a top portion of an equal number of ply members of a stiff sheet material adhesively secured together with a hinge and adhesive between the top ply member of the base and the bottom ply member of the top portion. The protective coating covers the top portion cut edge adjacent to the top ply of the base and preferably covers the upper surfaces of the base and top portions.
BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described with reference to the accompanying drawings in which:
FIG. 1 is a perspective view of a corner post according to the invention;
FIG. 2 is a slightly enlarged cross-sectionalview of the corner post illustrated in FIG. 1; and 7 FIG. 3 is a schematic representation of the method of making the corner post according to the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, and to FIGS. 1 and 2 in particular, there is illustrated a corner post 12 having a base member 14 and a top member 16. The base member is formed from a plurality of equal size relatively stiff corrugated board plies which are adhesively secured together. As used herein, equal size ply refers to ply of equal shapes in length and width dimensions but not necessarily of equal thicknesses. The top member 16 is adhesively secured to the base member 14 through adhesive 26. One longitudinal edge of the top member [6 lies in a common plane with one longitudinal edge of the base member 14 with plies of each top and base members being parallel to each other. As seen in the drawings, the top member is narrower than the base member, thereby forming an L-shaped configuration in cross-section with an upper surface 20 of base member 14, a surface 21 of the top member 16 and an abrasive side edge 22 of the top member 16. The corner post is used in boxes to protect the edges of articles. Ordinarily, the corner post would fit into a vertical corner of a box with surface 20, edge 22 and perhaps surface 21 in contact with the product to be protected. In conventional corner posts, these surfaces and edges are quite dirty because the cutting of the edge 22 leaves sawdust in the crevices of edge 22. Further, the edge 22 is quite abrasive and may normally mar the surface of the product which it abuts. To eliminate these problems, a protective coating is applied to surfaces 20 and 21, and to edge 22. The coating appears slightly exaggerated in FIG. 2 for purposes of illustration. The protective coating is a soft waxy or plastic substance which is sprayed on to the upper surfaces 20 and 21 and the side edge 22 after formation of the corner post. The protective coating is a water base coating emulsion containing paraffin or other similar protective components. This coating protects the product against abrasion from the edge 22 and surfaces 20 and 21 as well as seals dust and dirt within the side edge 22.
Reference is now made to FIG. 3 which illustrates the manner in which the corner posts are formed and the I method of the invention. A stack of corrugated board 30, formed from a plurality of adhesively secured corrugated plies of equal size, is fed to a sawing operation. If desired, the stack can be first cut laterally to the desired length of the corner post prior to the longitudinal sawing operation. A saw 32 cuts a longitudinal slot 34 in the stack 30 as the sheet moves through the sawing step. A second saw 35 completely cuts the stack 30 to the desired width. The stack is then passed beneath an adhesive depositing head 36 which supplies strips of adhesive 26 to an upper surface of the stack 30 on either side of the slot 34. Adhesive is fed to the depositing head 36 from an adhesive supply line 38. The stack 30 is divided into a wide portion 14a and a narrow portion 16a by the longitudinal slot 34. This longitudinal slot extends from the bottom of the stack 30 through the bottom portion of the upper-most ply of the stack, but not through the top surface of the stack 30, leaving a hinge l8 therebetween.
The stack 30 is then moved past a folding curl 40 which lifts the narrow portion 160 upwardly, rotating the narrow portion 16a about the hinge 18 until the stack surfaces containing the adhesive 16 are in contact with each other. The folded stack may then be passed beneath a pressure roller 42 for pressing the narrow portion 16a into firm engagement with the wide portion 140 for secure bonding of the glued surfaces. The folded stack thus forming a corner post is then moved to a spraying zone wherein the protective coating is applied. A spray nozzle 44 sprays a wax emulsion 46 onto the upper surfaces of the corner post thus formed and onto the side edge 22 of the narrow portion 160 to form the protective coating 24 (FIG. 2).
The forming operation illustrated in FIG. 3 shows the manner in which one length of corner posts can be formed. In actual practise of the invention, a plurality of such lengths will be simultaneously formed from a single sheet of corrugated board. In such operation, a plurality of similar devices illustrated in FIG. 3 are horizontally spaced across a table and identical operations are carried out simultaneously. Saws 35 separate each length of corner post and completely cut through the stack 30 as it passes the cutting stage in the operation to separate the lengths of corner posts. In this manner, the novel corner posts of the invention can be quickly and easily formed in an automated operation from a conventional stack of uniform thickness corrugated board. The corner post of the invention is thus adapted to a simple automated operation for lower cost production.
After a length of corner post has been made as described above, the corner post is preferably cut to a desired length by conventional means (not shown) such as a saw or a knife.
As seen in FIGS. 1 and 2 of the drawings, the corrugations of the plies extend alongthe length of the top member 16 and base member 14. The main compressive strength of the corner posts thus lies along the length of the corner post, or, in other words, in a direction parallel to the hinge 18.
The coating composition of the invention is soft and non-abrasive. Suitable compositions include emulsion or solutions of wax, low molecular weight poly l-olefins such as polyethylenes and low durometer vinyls. The composition is preferably sprayed onto the surfaces of the corner post so that the composition penetrates the crevices of the sawed side edge 22 and seals the side edge to retain the sawdust within the corner post. An example of a suitable paraffin emulsion is manufactured by Kalamazoo Paraffin Company as coating emulsion 60051-7. This emulsion has a viscosity of about 50 cps, a solids content of about 24.6 and a pH of about 9.6. Other suitable emulsions will have a viscosity into the range of about 25 cps.
Although the coating composition is preferably sprayed onto the corner post surfaces, other less preferred application methods can also be employed. For example, the coating can also be brushed or rolled onto the desired surfaces.
Whereas the method of the invention has been described with respect to a sawing operation, obviously, other forms of cutting can be employed. For example, knives or knife edges can be used in lieu of the saws.
Reasonable variation and modification are possible within the scope of the foregoing disclosure, the drawings, and the appended claims without departing from the spirit of the invention.
The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:
l. A corner post construction for use in internal packaging of cartons and the like between the vertical corners of the boxes and the products to be packaged in said cartons, said corner post construction comprising:
a base member formed from at least three equal size first ply members of a flat stiff corrugated sheet material stacked and adhesively secured in superimposed relationship to each other, said ply members forming a block of uniform dimensions throughout;
a top member formed from at least three second ply members of a flat stiff corrugated sheet material equal to that of said first ply members, said second ply members stacked and adhesively secured in superimposed relationship with respect to each other,
- each of said second ply members being of an equal size and of a length equal to that of said first ply members but substantially narrower in width;
said top member being adhesively secured to a top ply of said base member such that one longitudinal edge of said top member is in a common plane with a longitudinal edge of said base member and said first and second ply members are substantially parallel to each other, thereby forming an L-shaped corner post in cross-section with an opposite longitudinal edge of said top member adjacent to an upper surface of said base member;
said corrugations of said first and second ply mem-- bers extending in a direction parallel to said longitudinal edges of said top member and said base member;
a hinge joining the top ply of said base member with the bottom ply of said top member along said common plane; and
a protective coating of a relatively soft, non-abrasive material substantially completely covering and sealing at least said opposite edge of said top member, thereby protecting said products from the abrasive nature and dirt associated with said opposite longitudinal edge of said top member.
2. A corner post construction according to claim 1 and further comprising a protective coating covering the exposed upper surface of said base member.
3. A corner post construction according to claim 2 and further comprising a protective non-abrasive coating covering the upper surface of said top member.