NAIL

Abstract: Nail with a strengthened removal preventing force. Most of conventional nails are provided with a removal preventing means such as a spiral groove or annular grooves formed on the end of the shank thereof. When a base material into which the conventional nail is driven is a porous soft substance such as foamed concrete, the removal preventing means of these previous types do not provide a sufficient removal preventing force and little removal preventing effect is expected. This nail includes a pair of shanks (1), (1) longitudinally confronting each other with a band-like metal plate (2) therebetween, the ends of the shanks (1), (1) being formed with tapered surfaces (5) on the insides. Thus, when the nail is driven into a base material (9), the shanks (1), (1) are gradually diverged into the base material (9), while the metal plate (2) is compressed and deformed in a zigzag shape to thereby retain the expanding action of the shanks (1), (1) from the inside and to engage the shanks (1), (1) in the base material (9), thereby preventing the removal of the nail and strengthening the removal preventing force of the nail. Further, the nail also includes a tightening ring (7) disposed around both shanks (1), (1) and the metal plate (2), thereby preventing the shanks (1), (1) from expanding on the surface of the base material (9) and thus aiding the shanks (1), (1) to penetrate deep into the base material (9) as well as preventing the nail hole on the surface of the base material (9) from expanding.

Description: Nail Field of the Invention: The present invention relates to the structure of a nail to be driven into wall surfaces, etc. of a building which, after being driven in, exhibits very powerful countering force against its. coming-off, and which particularly, has large enough resistance or countering effect to its coming-off in any base material like expanded concrete which is soft and porous. Description of the Prior Art: Old nails were inadequate, because, having smooth circumferential surface around its shank, such a nail often comes off from the base material into which it has been driven. In order to prevent this coming-off, a nail provided around the circumferential surface of the root of its shank with the means for countering its coming-off including spiral grooves ring-shape grooves or protruded stripes, etc. has been developed. The means for countering the coming-off of this type provides adequate countering force against the coming-off in such a base material as wood, but in soft, porous materials like expanded concrete, the countering effect against the coming-off could hardly be expected because of the small friction between the nail and the base material and so the small countering force against its coming-off. Disclosure of the Invention: The nail of this invention has a pair of nail shank pieces united face to face through an intermediary of a strip metal, with the facing surfaces of the tip parts of the both nail shank pieces tapered. iEen this nail is driven into such a soft and porous base material as expanded concrete, not only the both nail shank pieces open to both sides, but the metal strip undergoes com pressive deformations, thereby holding their opened state from the inside. Accordingly, the both nail shank pieces engage with the base material in a dovetail fashion, providing powerful countering force against the nail's coming-off. The nail of this invention has a clamping ring which is put around the outer circumference of the both nail shank pieces holding the metal strip therebetween. This clamping ring, placed at the surface part of the base material, prevents the both nail shank pieces from opening at the base material surface part, and aids in the both nail shank parts'entering deep into the base material as well as preventing the expansion of the opening made by the nail at the base material surface. Brief Descriptidn of the Drawings: Figure 1 is a front view of the nail of this invention; Figure 2 is a sectional view of the nail along the line II - II of Figure 1; Figure 3 is a front view showing the configuration of the nail when completely driven in; and Figures 4 through 6 are explanatory views showing how the nail driving proceeds. The Best Configuration according to This Invention: Figure 1 through 3 represent the structure of the nail of this invention. In the nail structure illustrated by these views, a pair of nail shank pieces (1) (1) each having a semicircular shank piece section are faced to each other with their flat sides turned inward, a thin strip metal (2) is interposed between both nail shank pieces (1) (1), and three parts are closely integrally put together. The metal strip (2) is formed of such metal as copper, stainless steel, etc., with its width made identical with the nail shank's (1), but its length somewhat shorter than the latter's. On the root parts of the both nail shank pieces (1) (1), a fixing ring (3) is fit and set, to form the nail head part (4); on the other hand, at the tip part of the both nail shank pieces (1) (1), respectively symmetrical tapered surfaces (5) (5) are formed on their facing sides, so that the outer edge sides of the tips of the nail shank pieces (1) (1) are sharpened, and an outwardly flaring opening (6) is formed between the facing tapered surfaces (5) (5). In the nail structure of this invention, a washerlike clamping ring (7) is closely fit on the circumferential surfaces of the bottom parts of the both nail shank pieces (1) (1) holding the metal strip (2) therebetween. This clamping ring (7) holds the both nail shank pieces (1) (1) and the metal strip (2) in close contact with each other, and as the nail is driven in, the ring is pressed by the base material, in effect, to move up in the axial direction along the circumference of the both nail shank pieces (1) (1). Industrial Utility: Figures 4 through 6 exhibit how a structural member (8) is securely set in place on the surface of such a soft and porous base material (9) as expanded concrete. At the initial stage of driving in the nail into the base material (9), both nail shank pieces (l) (1) will go straightly into the base material (9) in the state of being closed (Figure 4) because the base material is soft. As the tip of the nail enters into the base material (9) deeper and deeper, the material placed in the entering path of the nail is subjected to the thrusting and the pinching pressures by the tapered surfaces (5) (5) of its tip parts; the material, then, will be compressed and hardened, to be mole compact, as compared with the surrounding part of the material. Then on the tapered surfaces (5) (5) of the tip parts of the both nail shank pieces (1) (1), the counter force from the hardened material (10) is exerted in the vertical direction; this force separates the facing nail shank pieces (1) (1), pushing them outwardly from each other as the driving of the nail proceeds (Figure 5). As the tip parts of the nail shank pieces (1) (1) start opening, the counter force of the hardened material (10) acts upon the metal strip (2) placed between the nail shank pieces (1) (1). The metal strip (2) undergoes compressive deformations sinuously in response to the nails driving in, filling the gap between the both nail shank pieces (1) (1) in cooperation with the hardened material (10). Accordingly1 the nail shank pieces (1) (1) are opened outwardly wider and wider, finally to engage with the base material (9) in a dovetail fashion as the nail has been completely driven thereinto (Figure 6). The clamping ring (7) is pressed by the structural member (8) in response to the driving-in of the nail, 1Tr'ffect, to move up on the nail shank pieces (1) (1), so that it always stays at the surface part of the structural member (8). Thus this Ting prevents the opening of the both nail shank pieces (1) (1) at the surface part of the base material (9). Accordingly, it not only aids in the both nail shank pieces'(l) (1) entering deep into the base material (9), but also serves to prevent the opening made by the nail at the surface of the base material (9) from growing larger. The nail shank pieces (1) ( thus driven into the base material (9) are held in their opened state under the powerful counter forces of the sinuously deformed metal strip (2) and the hardened material (10), and in proportion to these forces, the frictional resistance between the nail shank (1) and the base material increases. It is for this reason that the nail of this invention exhibits such a large counter force against its comng-off that its drawing-out is impossible once it has been driven in. The nail of this invention is not only formed of Åa material which undergoes a plastic deformation (permanent deformation) as it has been completely driven into the base material (9), but the size and the sectional shape of the nail shank (1) are appropriately chosen, so that its dovetail fashion engagement with the base material (9) -may be semipermanently maintained.

Claims: What Is Claimed Is: (1) A nail having a pair of nail shank pieces (1) (1) united face to face through the intermediary of a strip metal (2), with tapered surfaces (5) (5) formed on the facing sides of the tip parts of both nail shank pieces (1) (1), and a clamping ring (7) put around the outer circumference of the both nail shank pieces (1) (1) holding a metal strip (2) therebetween. (2) A nail according to Claim (1) wherein a fixing ring is fit, and set in place around the outer circumference of the root parts of the both nail shank pieces (1) (1). (3) A nail according to Claim (1) or (2) wherein the both nail shank pieces (1) (1) are formed of a material which will undergo a plastic deformation as they have been driven in.

Inventors: HASEGAWA, TAKEO
Applicants: WAKAI INDUSTRY CO. LTD.
Application year: 1981
Main classification: F16B15
IPC codes: F16B15