Wire nail

Abstract: A wire nail (10) having a shank (12), a head (14) formed on one end of the shank, and a point (16) formed on the other end. The point has a penetrating portion, a wedging portion, and a transitional portion. The wedging portion defines four straight edges, each being inclined at an acute angle relative to an axis defined by the shank. The transitional portion defines four straight edges, each meeting a different one of said edges defined by the wedging portion, and each being inclined at a lesser angle relative to the same axis. The wedging portion has a plurality of convex surfaces, each conforming generally to a section of a circular cylinder. The transitional portion has a plurality of convex surfaces, each conforming generally to a section of a circular cylinder. A cutting tip is formed as a thin rib extended across the penetrating portion. A pair of thin cutting ribs extended from the cutting tip are formed along the wedging and transitional portions.

Description: Technical Field of the Invention This invention pertains to wire nails, particularly but not exclusively wire nails designed to be forceably driven by pneumatic powered or combustion-powered nailing tools. Background of the Invention For many years, wire nails have been used in countless numbers for wood-fastening and other applications. Pneumatically powered nailing tools and, in recent years, combustion-powered nailing tools have been used extensively to drive such nails. Typically, wire nails are made from steel wire with a shank defining an axis, a head formed on one end of the shank, and a point formed on the other end of the shank. Although various points have been known, a standard point has evolved, which is characterized by four flat, triangular facets, each lying in a plane oriented at an angle of about 20° relative to an axis defined by the shank. Such a point tends to be quite sharp. The prior art document US 3,966,042 discloses a compactly collated strip of wire nails having D-shaped heads. Accordingly a wire nail is known having a shank with opposite ends, a head formed on one of the ends, and a point formed on the other end, the shank defining an axis. Many efforts have been made to increase the resistance of such nails to withdrawal. Such efforts have been focused primarily on their shanks, which consequently have been coated, etched, spirally grooved, annularly grooved, or barbed, so as to increase their resistance to withdrawal. Divers coating agents have been used to increase such resistance, e.g., poly(vinyl acetate). Blunt pointed nails have been used to minimize splitting of wood. Although wire nails as known heretofore have proved to be generally satisfactory for many applications, their utility would be greatly enhanced if their resistance to withdrawal could be further increased. It is therefore in object of this invention to provide a wire nail with increased resistance to withdrawal. This object is solved by a wire nail according to claim 1. Advantageous embodiments of the invention are subject of the dependent claims. Summary of the Invention Surprisingly, it has been found that point geometry of a nail has a significant effect on the resistance of the nail to withdrawal, whether or not the shank of the nail has been coated. Accordingly, this invention provides a wire nail having a novel point and tending to have greater resistance to withdrawal, when tested with different types of wood, as compared to a wire nail having a standard point. The wire nail provided by this invention is similar to prior nails in having a shank, which defines an axis, a head, which is formed on one end of the shank, and a point, which is formed on the other end of the shank. The shank may be optionally coated, etched, spirally grooved, annularly grooved, or barbed, as mentioned above. Preferably a portion of the shank is circular in cross-section, up to the end on which the point is formed. The head may conform to the heads of prior nails. However, the point differs significantly from a standard point, as mentioned above, and from other known points. Specifically, the point has a penetrating portion, a wedging portion, and a transitional portion. The penetrating portion is blunt, although a cutting tip may be optionally formed on the penetrating portion, as mentioned below. The wedging portion merges with and tapers toward the penetrating portion. The transitional portion merges with and tapers toward the wedging portion and merges with the shank end on which the point is formed. The wedging portion defines plural straight edges, preferably four straight edges, each of which is inclined at a given angle relative to the axis defined by the shank, Preferably an acute angle relative to the axis defined by the shank. Preferably, the acute angle is about 12 1/2°, i.e., 12.5°. Although four such edges are preferred, it is contemplated that two, three, or more than four such edges may be alternatively used. The transitional portion defines plural straight edges, preferably four straight edges, each of which meets a different one of such edges defined by the wedging portion, and each of which is inclined at a lesser angle relative to the angle defined by the shank. Preferably, the lesser angle is about 10°. Although four such edges are preferred, it is contemplated that two, three, or more than four such edges may be alternatively used. The wedging portion has a plurality of convex surfaces. Each such surface conforms generally to a section of a circular cylinder, preferably a circular cylinder defining a central axis passing through the wire nail. Two such surfaces meet at each of such edges defined by the wedging portion. The transitional portion has a plurality of convex surfaces. Each such surface on the transitional portion conforms generally to a section of a circular cylinder, preferably a cylinder defining a central axis passing through the wire nail. Two such surfaces of the transitional portion meet at each of such edges defined by the transitional portion. Preferably, each of the penetrating, wedging, and transitional portions of the point is elongate in cross-section, and asymmetrical about the axis defined by the shank. Preferably, as mentioned above, a cutting tip is formed on the penetrating portion. The cutting tip way be advantageously formed on the penetrating portion as a thin rib extending across the penetrating portion. If a cutting tip is formed as mentioned above, the wire nail may have a pair of cutting ribs extended from the cutting tip and formed along the wedging portion, preferably between two of such edges defined by the wedging portion. Such ribs may be also formed along the transitional portion, preferably between two of such edges defined by the transitional portion. A wire nail according to this invention tends to exhibit greater resistance to withdrawal, when tested with different woods, as compared to a wire nail having a standard point. Wire nails according to this invention can be suitably collated, in known ways, so as to be particularly useful with pneumatically powered and combustion-powered nailing tools having suitable magazines. These and other objects, features, and advantages of this invention are evident from the following description of the preferred embodiment of this invention, with reference to the accompanying drawing. Brief Description of the Drawing FIGURE 1 is a perspective view of the wire nail constituting a preferred embodiment of this invention. The wire nail is shown as having a cylindrical shank, a D-shaped head formed on one end of the shank, and a novel point formed on the other end of the shank. FIGURES 2 and 3 are greatly enlarged, fragmentary, elevational views, which are taken in mutually orthogonal directions, and which show details of the novel point. FIGURE 4 is an end view, which is taken in a direction facing the novel point. FIGURES 5, 6, and 7 are sectional views which are taken respectively along lines 5--5, 6--6, and 7--7 in FIGURE 2, each in a direction indicated by arrows. FIGURES 8A, 8B, 8C, and 8D are end views of wood boards differing from each other in grain structures. FIGURES 9 and 10 are graphical representations of certain data obtained in certain tests. Detailed Description of Preferred Embodiment As shown in FIGURE 1, a wire nail 10 constituting a preferred embodiment of this invention has a shank 12, a head 14 formed on one end of the shank 12, and a point 16 formed on the other end of the shank 12. The head 14 and the point 16 may be die-formed on opposite ends of the shank 12 in a nail-making machine (not shown) of a known type, e.g., a Wafios Model N51 Nail-Making Machine, as available commercially from Wafios Maschinenfabrik GmbH & Co. KG of Reuthingen, Federal Republic of Germany. The shank 12 conforms generally to a circular cylinder of a given diameter (e.g., 0,0032639 m (0.1285 in.)) and defines an axis, which is the central axis of such cylinder. Two points on such axis are indicated in the drawing, namely, where such axis passes through an intersection of two straight (phantom) lines shown in FIGURE 7 and where such axis passes through an intersection of two straight (phantom) lines shown in FIGURE 6. The shank 12 may be optionally coated, etched, spirally grooved, annularly grooved, or barbed, as mentioned above, so as to increase the resistance of the wire nail 10 to withdrawal. The head 14 is D-shaped, as shown in FIGURE 1. Thus, the wire nail 10 and like nails (not shown) may be compactly collated, in known ways, so as to be particularly useful in a pneumatically powered or combustion-powered nailing tool (not shown) having a suitable magazine (not shown) to receive a collated strip of such nails. See, e.g., Shelton et al. U.S. Patent No. 3,966,042 for an example of a compactly collated strip of wire nails having D-shaped heads. However, the point 16 differs significantly from a standard point, and from other known points, and has a penetrating portion 18, a wedging portion 20, and a transitional portion 22. The penetrating portion 18 is rounded, and blunt, except for a thin rib 24 to be later described. The wedging portion 20 merges with and tapers toward the penetrating portion 18. The transitional portion 22 merges and tapers toward the wedging portion 20 and merges with one end of the shank 12, i.e., the end on which the point 16 is formed. The wedging portion 20 defines four straight edges 26 a , 26 b , 26 c , 26 d , each of which is inclined an an acute angle of about 12 1/2° relative to the axis defined by the shank 12. The transitional portion 22 defines four straight edges 28 a , 28 b , 28 c , 28 d , each of which is inclined at a lesser angle of about 10° relative to the axis defined by the shank 12. The edge 28 a of the transitional portion 22 meets the edge 26 a of the wedging portion 20. Also, the edge 28 b meets the edge 26 b , the edge 28 c meets the edge 26 c and the edge 28 d meets the edge 26 d . The wedging portion 20 has a convex surface 30, which is bounded laterally by the edges 26 a , 26 b , and a convex surface 32, which is bounded laterally by the edges 26 c , 26 d , as well as a convex surface 34, which is bounded laterally by the edge 26 a and by a rib 36 to be later described, and a convex surface 38, which is bounded laterally by the edge 26 c and by the rib 36. The wedging portion 20 also has a convex surface 40, which is bounded laterally by the edge 26 b and by a rib 42, to be later described, and a convex surface 44, which is bounded laterally by the edge 26d and by the rib 42. Each of such surfaces 30, 32, 34, 38, 40, 44 conforms generally to a section of a circular cylinder of a given radius (e.g., 0,0016256 m (0,064 in.)) which is equal for each of such surfaces 30, 32, 34, 38, 40, 44. The transitional portion 22 has a convex surface 50, which is bounded laterally by the edges 28 a , 28 b , and a convex surface 52, which is bounded laterally by the edges 28 c , 28 d , as well as a convex surface 54, which is bounded laterally by the edges 28 a and by the rib 36, and a convex surface 58, which is bounded by the edge 28 c and by the rib 36. The transitional portion 22 also has a convex surface 60 which is bounded laterally by the edge 28 b and by the rib 4 2 , and a convex surface 64, which is bounded laterally by the edge 28 d and by the rib 42. Each of such surfaces 50, 52, 54, 58, 60, 64, conforms generally to a section of a circular cylinder of a larger radius (e.g., 0,0024384 m (0,096 in.)) which is equal for each of such surfaces 50 52, 54, 58, 60, 64, and which is larger than the given radius for each of the convex surfaces if the wedging portion. Each of the penetrating, wedging, and transitional portions of the point 16 is elongate in cross-section, and asymmetrical about the axis defined by the shank 12, as shown in FIGURES 5 through 7. Thus, in any cross-sectional plane taken through the wedging portion 20 and in normal relation to the axis defined by the shank 12 (see, e.g., FIGURE 6) a straight line connecting the edges 26 a , 26 d , and a straight line connecting the edges 26 b , 26 c , intersect (at the axis defined by the shank 12) at unequal supplementary angles of about 60°, 120°. Also, in any cross-sectional plane through the transitional portion 22 and in normal relation to the axis defined by the shank 12 (see, e.g., FIGURE 7) a straight line connecting the edges 28 a , 28 d , and a straight line connecting edges 28 b , 28 c , intersect (at the axis defined by the shank 12) at unequal supplementary angles of about 60°, 120°. As mentioned above, a cutting tip is formed on the penetrating portion 18, as a thin cutting rib 24 formed with substantially square (about 90°) edges and extended across the penetrating portion 18 at the narrowest dimension of such portion 18. As mentioned above, a pair of thin cutting ribs 36, 42, are formed with substantially square edges (about 90°) and extend to opposite ends of the rib 24 (with which the ribs 36, 42, merge at a cross-sectional plane through line 5--5 of FIGURE 2) along the wedging portion 20, the rib 36 extending about equally between the edges 26 a , 26 c , and the rib 42 extending about equally between the edges 26 b , 26 d , and along the transitional portion 22, the rib 36 extending about equally between the edges 28 a , 28 c , and the rib 42 extending about equally between the edges 28 b , 28 d . Preferably, the cutting rib 24 forming the cutting tip and the cutting ribs 36, 42, have a uniform thickness of about 0,0000762 m (0.003 inch) and the cutting rib 24 forming the cutting tip extends axially by about 0,000254 m (0.01 inch) . Preferably, except for the cutting rib 24 forming the cutting tip, the point 16 has an axial length of about 0,006477 m (0.255 inch), except for the cutting rib 24 forming the cutting tip, there is an axial distance of about 0,00508 m (0.2 inch) between a cross-sectional plane through line 7--7 of FIGURE 2 and the extreme end of the penetrating portion 18, and there is an axial length of about 0,00254 m (0.1 inch) between a cross-sectional plane through line 6--6 of FIGURE 2 and the extreme end of the penetrating portion 18. Such a nail is susceptible to various dimensional, proportional, and other modifications. Comparative Examples Tests were conducted to compare wire nails according to the preferred embodiment of this invention, as described above, and wire nails according to the prior art, as formed with standard points. As mentioned above, a standard point is characterized by four flat, triangular facets, each lying in a plane oriented at an angle of about 20° relative to the axis defined by the shank of the nail having such a point, and such a point tends to be quite sharp. As tested, such nails according to the preferred embodiment of this invention and such nails according to the prior art were similar, except for their points. Each measured about 0,0762 m (3.0 inches) in its overall length and had a shank diameter of about 0,0033274 m (0.131 inch). Each was coated similarly, along its point and adjacent portions of its shank so as to have a coated length of about 0,03175 m (1.25 inches), with Inducote™ 13-076 poly(vinyl acetate) coating material, as available commercially from Finnaren & Haley, Inc., of Conshohocken, Pennsylvania. Example One - S-P-F Tests A first group of such nails according to the preferred embodiment of this invention and a first group of such nails according to the prior art were driven into S-P-F boards. Here "S-P-F" is an art-recognized term for certain Spruce, Pine, and Fir species having specific gravities within narrow ranges; see International Staple, Nail and Tool Association, Bulletin No. UM-25d (undated). The S-P-F boards were selected to have close similarities in grain structure, which was judged visually at the board ends, in specific gravity, which ranged from about 0.39 to about 0.43 inclusive, and in moisture content, which ranged from about 7.5% to about 10% inclusive. Each such S-P-F board had a grain structure similar to the grain structure shown in FIGURE 8B; boards having grain structures similar to any of the grain structures shown in FIGURES 8A, 8C, and 8D were rejected. Two nails from the first group of such nails according to the preferred embodiment of this invention and two nails from the first group of such nails according to the prior art were driven into each of fifteen such S-P-F boards. Each such nail was driven by a Paslode™ Model 5350S pneumatically powered nailing tool. The same tool, which was operated at a tool pressure of 689476 Pa (100 psi), was used to drive each such nail. Paslode™ Model 5350S pneumatically powered nailing tools are available commercially from ITW-Paslode of Lincolnshire, Illinois. Withdrawal force for each such nail was measured within a few hours after such same nail had been driven, by a Tinius Olsen Model Super "L" testing machine, as available commercially from Tinius Olsen Testing Machine Company, of Willow Grove, Pennsylvania. See Strimel U.S. Patent No. 2,808,721 for a description of such a machine. Wood conditions were as tabulated in Table A below. Board No. 1 2 3 4 5 6 7 8 Moisture (%) 10.0 9.5 9.5 10.0 8.5 8.5 7.5 9.0 Specific Gravity 0.42 0.43 0.43 0.41 0.40 0.41 0.43 0.41 Board No. 9 10 11 12 13 14 15 Moisture (%) 8.5 10.0 9.5 10.0 8.5 9.0 7.5 Specific Gravity 0.39 0.41 0.41 0.39 0.39 0.38 0.40 The data tabulated in Tables B and C below were obtained. No wood splits, head popping, or shank breaking were observed. Some of such data are abstracted in FIGURE 9, which plots average (mean) values of withdrawal forces (in pounds per inch) for individual S-P-F boards, in ascending order, and in which the upper plot represents such values (in ascending order) for the S-P-F boards and tested nails according to the preferred embodiment of this invention, and in which the lower plot represents such values for the same boards and tested nails according to the prior art. (Please note following conversion units as applied to Tables B, G, E, F and Fig 9 and 10: 1 inch = 0,0254 m, 1 lb = 0,45359 kg, 1 lb/inch= 17,858 kg/m.) Example Two - Oak Tests A second group of such nails according to the preferred embodiment of this invention and a second group of such nails according to the prior art were driven into Oak boards. The Oak boards were selected to have close similarities in grain structure, which was judged visually at the board ends, in specific gravity, which ranged from about 0.67 to about 0,73 inclusive, and in moisture content, which ranged from about 31% to about 40% inclusive. Each such Oak board had a grain structure similar to the grain structure shown in FIGURE 8B; boards having grain structures similar to any of the grain structures shown in FIGURES 8A, 8C, and 8D were rejected. Three nails from the second group of such nails according to the preferred embodiment of this invention and three nails from the second group of such nails according to the prior art were driven into each of ten such Oak boards by the Paslode™ Model 5350 S pneumatically powered nailing tool noted above. The same tool , which was operated at a tool pressure of 689476 Pa (100 psi) was used to drive each such nail. Withdrawal force for each such nail was measured by means of the Tinius Olsen Super "L" testing machine noted above, within a few hours after such same nail had been driven. Wood conditions were as tabulated in Table D below. Board No. 1 2 3 4 5 6 7 8 9 10 Moisture (%) 37 34 33 40 31 34 38 39 34 32 Specific Gravity 0.69 0.72 0.67 0.67 0.72 0.73 0.68 0.70 0.67 0.72 The data tabulated in Tables E and F below were obtained. Wood splits, when observed, were noted. No head popping or shank breaking was observed. Some of such date are abstracted in FIGURE 10, which plots average (mean) values of withdrawal forces (in pounds per inch) for individual Oak boards, in ascending order, and in which the upper plot represents such values (in ascending order) for the Oak boards and tested nails according to the preferred embodiment of this invention and the lower plot represents such values for the same boards and tested nails according to the prior art. The following data were obtained for the second group of wire nails according to the prior art:

Claims: A wire nail (10) having a shank (12) with opposite ends, a head (14) formed on one of the ends, and a point (16) formed on the other end, the shank (12) defining an axis; characterized in that the point (16) having a penetrating portion (18), a wedging portion (20), which merges with and tapers toward the penetrating portion (18), and a transitional portion (22), which merges with and tapers toward the wedging portion (20) and merges with the last-mentioned other end of the shank (12), the wedging portion (20) defining plural straight edges (26a, 26b, 26c, 26d), each of which is inclined at a given angle relative to the axis defined by the shank (12), the transitional portion (22) defining plural straight edges (28a, 28b, 28c, 28d), each of which meets a different one of said edges (26a, 26b, 26c, 26d), defined by the wedging portion (20), the penetration portion (18) being blunt and the wedging portion (20) having a plurality of convex surfaces (30, 32, 34, 38, 40, 44), each of which conforms generally to a section of a circular cylinder, and two of which meet at each of said edges (26a, 26b, 26c, 26d), defined by the wedging portion (20), each of the straight edges (28a, 28b, 28c, 28d) defined by the transitional portion (22) being inclined at a lesser angle than the given angle relative to the axis defined by the shank (12), and the transitional portion (22) having a plurality of convex surfaces (50, 52, 54, 58, 60, 64), each of which conforms generally to a section of a circular cylinder, and two of which meet at each of said edges (28a, 28b, 28c, 28d), defined by the transitional portion (22). A wire nail of claim 1 characterized in that the wedging portion (20) defining four straight edges (26a, 26b, 26c, 26d), each of which is inclined at an acute angle relative to the axis defined by the shank (12) and the transitional portion (22) defining four straight edges (28a, 28b, 28c, 28d). The wire nail of claim 2 characterised in that each of the Penetrating portion (18), wedging portion (29) and transitional portion (22) of the point (16) is elongate in cross-section, and asymmetrical about the axis defined by the shank (12). The wire nail of claims 2 or 3 characterized in that the acute angle is about 12 1/2° and the lesser angle is about 10°. The wire nail of claims 2, 3 or 4 characterised by a cutting tip formed on the penetration portion (18). The wire nail of one of the claims 2 to 5 characterised in that the cutting tip is formed as a thin rib (24) extended across the penetrating portion (18). The wire nail of one of the claims 2 to 6 characterised by a pair of thin cutting ribs (36, 42) extended from the cutting tip and formed along the wedging portion (20). The wire nail of claim 7 characterised in that each of the cutting ribs (36, 42) is formed along the transitional portion (22) as well. The wire nail of one of claims 6 to 8 characterised in that the ribs (24, 36, 42) are formed with substantially square edges. The wire nail of one of claims 7 to 9 characterised in that each of the cutting ribs (36; 42) extends about equally between two of said edges (26a, 26c; 26b, 26d) defined by the wedging portion (20). The wire nail of one of claims 7 to 10 characterised in that each of the cutting ribs (36; 42) extends along the transitional portion (22), about equally between two of said edges (28a, 28c; 28b, 28d) defined by the transitional portion (22).

Inventors: SYGNATOR HENRY A C O PATENT AT, SYGNATOR, HENRY A., C/O PATENT ATTORNEYS
Applicants: ILLINOIS TOOL WORKS, ILLINOIS TOOL WORKS INC.
Application year: 1990
Main classification: F16B15
IPC codes: B25C1, F16B15, B21G3