JPH0622608U - Knurled nails - Google Patents

Abstract

(57) [Abstract] [Purpose] Especially, the shear strength of the valley part is increased by the concentration of the stress applied to the valley part of the knurl engraved on the outer peripheral surface of the nail shaft part, and it acts on the nail shaft part from the lateral direction. To provide knurled nails that are strong against shocks. A knurled nail having a head portion, a shaft portion, and a sharp end portion, and at least a part of the outer peripheral surface of the shaft portion having knurls engraved, the shaft portion being heat-treated at HV hardness of about 600 or more, and a central portion, HV hardness is 460 to 500 on the outer peripheral side of the center of the knurled portion, and H is H at the depth approximately the same as the height of the knurled peak from the surface.
A decarburized layer whose hardness is gradually changed so that V hardness of 530 to 570 is maintained is formed.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a knurled nail in which at least a part of a shaft portion is formed with a knurl, and more particularly to a knurled nail in which the shear resistance of a knurled portion is improved.

[0002]

[Prior art]

 Generally, there is known a knurled nail in which a knurl is engraved on the outer peripheral surface of the shaft to improve the frictional force with the material to be driven in order to improve the pulling resistance after the nail is driven (for example, Japanese Utility Model Publication No. 53). -4349, etc.). By forming knurls on the outer surface of the nail shaft, stress concentration occurs in the valley formed by the knurled ridges, the shear strength of the nail shank decreases, and the nail shank is damaged by impact after construction. It is also known that there is a problem in that it causes segregation and impairs the reliability of nailing work. Therefore, the applicant has already applied for a device for forming the knurled valley portion of the knurled nail into a curved surface to disperse the stress concentration in the valley portion. (Actual application No. 1-151131)

[0003]

[Problems to be solved by the device]

 However, of the above knurled nails, especially in the case of knurled nails in which the material to be driven is a steel plate, the nail shaft has been heat treated to withstand a large impact during driving, and The phenomenon of fracture from the valley of the knurl occurred even if the stress was not so large and concentrated. Therefore, when the outer wall plate is stopped by using the conventional knurled nails, the knurl portion breaks when receiving an external shock such as an earthquake. However, there was a problem that the nailing work was not reliable.

The present invention solves the above problems, and particularly increases the shear resistance of the trough portion by concentrating the stress applied to the trough portion of the knurl engraved on the outer peripheral surface of the nail shaft portion. Its purpose is to provide a knurled nail that is strong against impacts and the like that acts laterally.

[0005]

[Means for Solving the Problems]

 In order to solve the above problems, the present invention provides a knurled nail having a head portion, a shaft portion, and a tip portion, and at least a part of the outer peripheral surface of the shaft portion having knurls engraved, wherein the shaft portion has an HV hardness of about 600 or more. The heat-treated center part and the outer peripheral side of the center part of the knurled part have a HV hardness of 460 to 500 at the surface part and a HV hardness of 530 to 570 at a depth almost the same as the height dimension of the knurls from the surface. It is characterized in that a decarburized layer whose hardness is gradually changed so as to maintain

[0006]

[Action]

 The knurling nail according to the present invention maintains the HV hardness of 460 to 500 on the surface of the knurling part around the center portion which is heat-treated to a high hardness of HV hardness of 600 or more, and the height of the knurling peak from the surface. Since a decarburized layer with a gradually changing hardness was formed to maintain the HV hardness of 530 to 570 at a depth almost the same as the dimension of, the shear strength of the knurl was dispersed because the stress was dispersed in the valley. It is possible to prevent the nail shaft from being broken down.

[0007]

[Effect of device]

 The knurled nail according to the present invention does not easily disintegrate from the knurled portion of the nail shaft, especially from the valley of the knurled portion, even if it is impacted by an earthquake or the like when the outer wall plate is stopped in construction. Therefore, the reliability of the nailing work can be improved. Furthermore, by forming the valley portion of the knurled surface into a curved surface, it is possible to disperse the stress concentration in a region where the valley portion is small, and thus it is possible to obtain a knurled nail that can withstand a larger impact force.

[0008]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, A indicates a knurled nail. The knurled nail A is composed of a head portion 10, a shaft portion 11 and a tip portion 12, and the head portion 10 may have any of a normal flat head shape, a semi-round head shape, a round head shape, and a large flat head shape. It has a flat head. A knurled knurl 13 ′ formed by rolling or the like is engraved on an intermediate part of the shaft 11 except for the head 10 side and the tip 12 to form a knurled part 13. The tip of the tip portion 12 may have an arbitrary shape such as a bullet shape, a needle shape, a diamond cut shape, or the like that penetrates a steel plate, but in the illustrated embodiment, a point 14 processed into a diamond cut shape is formed.

The knurled portion 13 is composed of a ridge portion 15 that bulges outward from the outer peripheral surface of the shaft portion 11 and a valley portion 16 that is recessed in the axial direction from the outer peripheral surface of the shaft portion 11. Reference numeral 16 is formed as a curved surface 16 'to eliminate concentration of stress due to external force in the shearing direction. Further, the ridge portion 15 is formed as a curved surface 15 ′ in order to reduce the penetration resistance into the material W to be driven.

A straight non-knurled portion 17 having a diameter smaller than the outer diameter of the mountain portion 15 of the knurled portion 13 is formed between the tip portion 12 and the knurled portion 13, and the knurled portion of the shaft portion 11 is formed. 13 and the non-knurled portion 17 are continuous with a tapered knurled portion 18 in which the outer diameter of the crest portion gradually changes. The cross-sectional shape of the tapered knurled portion 18 is also formed with curved valleys and peaks.

As shown in FIG. 2, the entire nail shaft portion 11 on which the knurled portion 13 is formed is heat-treated at a high hardness of HV hardness of 600 or more, and further, a mountain of the knurled portion 13 is decarburized. The surface portion 19a of the portion 15 has an HV hardness of 460 to 500, and the surface portion 19a has a depth between the surface portion 19a and the bottom of the valley portion 16 of the knurled portion to the top of the mountain portion 15 (that is, the height of the knurled mountain portion). The decarburized layer 19 is formed so that the hardness of 19b is gradually changed so as to maintain the HV hardness of 530 to 570. The decarburized layer 19 is formed by a known decarburizing method such as heat-treating a knurled nail material in a hydrogen gas atmosphere for a predetermined time.

Next, the test results when a load is applied to the knurled nail A of the present invention and the conventional knurled nails B and C from the lateral direction with respect to the shaft will be described with reference to FIGS. 3 to 4. In this test, as shown in FIG. 3, a predetermined load F is applied to the upper material W in the direction of the arrow while the upper material W having a predetermined thickness is struck against the steel plate material S using a knurled nail. By applying a shearing force to the nail shaft, the relative slip amount between the upper material W and the steel plate material S was grasped, and the bent or broken state of the nail shaft was observed. The sample nail B used for comparison with the knurled nail A of the present invention has a HV hardness of 520 on the surface of the knurled ridge, and an HV hardness of the knurled nail at the depth approximately twice the ridge height. It is a knurled nail that has been decarburized so that it has the same hardness as that of the knurled portion. Similarly, the sample nail C has a knurled nail A of the present invention where the depth from the surface is twice the height of the knurl. It is a knurled nail that has been decarburized to have the same HV hardness as above and decarburized so that the HV hardness of the mountain surface is about 450.

The graph of FIG. 4 is a graph of the data obtained regarding the magnitude of the load F of each knurled nail and the amount of sliding displacement of the material by the above experiment, and the sample nail B shows a comparatively high holding ability. However, it became clear that in the state where the amount of slippage between the upper material W and the steel sheet material S was small, the nail shaft suffered a deposition loss and the holding force was completely lost thereafter. In addition, in the sample nail C, the amount of slippage between the upper material W and the steel sheet material S increases due to the bending of the nail shaft under a relatively weak load F, and as a result, the holding force itself becomes low. It was Further, in the case of the sample nail C, when the steel nail S is driven into the steel plate material S by using the power nailing machine, the bending of the nail shaft due to buckling occurs, which causes a problem in the driving process. The knurled nail A of the present invention is a knurled nail which has a sufficient holding capacity to withstand a relatively high load, but does not show the deposition loss of the nail shaft until the nail head comes off due to the breaking of the upper material, and has sufficient reliability. It became clear.

[Brief description of drawings]

FIG. 1 is a front view showing a knurled nail of the present invention.

FIG. 2 is a partial enlarged cross-sectional view of a knurled portion of the knurled nail of FIG.

FIG. 3 is a view showing a state in which a comparative experiment with a conventional knurled nail is performed.

FIG. 4 is a graph showing the above experimental data with respect to the magnitude of load and holding capacity.

[Explanation of symbols]

 A. Knurled nails 10. Head 11. Shaft 12. Tip 13. Knurl part 14. Point 15. Yamabe 15 '. Curved surface 16. Tanibe 16 '. Curved surface 17. Non-knurling part 18. Tapered knurled portion 19. Decarburized layer

Claims (2)

[Scope of utility model registration request] 1. A knurled nail having a head portion, a shaft portion, and a pointed portion, and at least a part of the outer peripheral surface of the shaft portion being knurled, wherein the shaft portion is heat treated at an HV hardness of about 600 or more. And gradually increasing the HV hardness of 460 to 500 on the outer peripheral side of the central portion of the knurled portion and maintaining the HV hardness of 530 to 570 at a depth almost the same as the height of the knurled peak from the surface. A knurled nail characterized in that it has a decarburized layer with varying hardness. 2. The knurled nail according to claim 1, wherein the valley portion of the knurled portion is formed of a curved surface.