JP2009014049A - Bolt, nut and processing method for bolt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To securely prevent a nut from coming off and being detached from a screw shaft part of a bolt and to facilitate fastening operation of the nut by an impact wrench, when the nut of the bolt with the nut used for a pipe clamp is loosened by the impact wrench. <P>SOLUTION: The nut 5 is spirally fitted to the bolt 4 from one end (free end 8a) of the screw shaft part 8. A swelling head part 12 for preventing coming off of the nut 5 is integrally formed on the one end (free end 8a) of the screw shaft 8 by pressurization in the axial center direction to crush a screw thread of the screw shaft part 8 without pre-processing an end face of the screw shaft part 8. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a bolt nut that is incorporated in various clamps for fastening members, the nut being tightened and loosened, and a method for processing the bolt.

  Fastening bolts and nuts are incorporated in pipe clamps used for assembling various temporary objects such as temporary scaffolds at construction sites, for example, pipe clamps that connect steel pipes that are assembly members to each other. The bolt of this fastening bolt nut is pivotally supported on the clamp base member at the head equivalent side, and a nut that is screwed into the bolt is used to tighten the pressing member pivotally supported on the base member so that the clamp member can be opened and closed. Is fixed to the steel pipe and the nut is loosened to open the pressing member with respect to the base member, and the clamp can be removed from the steel pipe. In recent years, tightening and loosening of nuts of pipe clamps is usually performed with an impact wrench, and there is no problem with the tightening operation of nuts. Since the screw shaft part margin length on the relaxation movement direction side is small, the nut that is unscrewed instantaneously at high speed comes off from the bolt. In order to solve such a problem, a method is known in which a small-diameter shaft portion in which the nut is idled is formed at one end of the screw shaft portion on the nut loosening movement direction side of the bolt.

  In the conventional method of forming a small-diameter shaft portion in which the nut rotates idly, it is troublesome to rotate the nut playing in the small-diameter shaft portion in the fastening direction so that the nut is smoothly screwed into the screw shaft portion. When trying to use a wrench, the nut tends to bite into the screw shaft portion in an inclined state and become unusable. In order to solve such problems, it was considered to adopt a method of forming a bulging head for nut removal prevention. However, since the nut cannot be assembled later, it is possible to prevent nut removal when rolling the bolt. The bulging head for nut removal or the bulging head for retaining the nut cannot be integrally formed at the time of cutting the shaft body before rolling the bolt. Therefore, conventionally, a depression or a cylindrical hole is formed in the end surface of one end of the screw shaft portion on the nut loosening movement direction side of the bolt, and press working is performed so that the circumference of the depression or the cylindrical hole is expanded from the inside to the outside. Thus, a method of forming a bulging head for retaining the nut was considered. However, in this method, when a nut that rotates in a relaxed direction with a strong rotational force is received by the bulging head for retaining the nut, the bulging head for retaining the nut tends to be reduced in diameter, and after repeated use May be deformed to the extent that the bulging head for retaining the nut does not function, and cannot be put to practical use.

  An object of the present invention is to provide a bolt and nut capable of solving the conventional problems as described above, and the bolt and nut according to claim 1 is denoted by reference numerals of embodiments to be described later. When the nut 5 is a bolt 4 screwed from one end (free end 8a) of the screw shaft portion 8, the end surface of the screw shaft portion 8 is connected to one end (free end 8a) of the screw shaft portion 8. The nut detachable bulging head 12 is integrally formed by pressurizing in the axial direction so as to crush the screw thread of the screw shaft portion 8 without pre-processing.

  The bolt nut according to the present invention described in claim 1 is the screw shaft of the bolt 4A in which the nut 5 is screwed from one end (free end 8a) of the screw shaft portion 8, as described in claim 2. The screw shaft portion 8 that is separated from one end (the free end 8a) of the portion 8 only by the region A that forms the bulging head 12 for preventing nut detachment is fitted into the screw groove and is held in a state where relative movement in the axial direction is impossible The screw in the region A is held by pressing the one end (free end 8a) of the screw shaft portion 8 in the axial direction without holding the other end of the screw shaft portion 8. The shaft portion 8b is compressed in the axial direction so that the bulging head portion 12 for preventing the nut from coming off can be integrally formed.

  According to the bolt nut according to the first aspect of the present invention, since the bulging head for nut removal prevention is integrally formed at one end of the screw shaft portion on the side on which the nut is screwed, the screw is unscrewed in the loosening direction. The removed nut can be prevented from coming off from the bolt by the axial contact between the outer end surface of the nut and the bulging head for retaining the nut. Therefore, since the nut is always screwed into the screw shaft portion even in a state where the nut is prevented from being detached, there is no need to screw the nut into the screw shaft portion when the nut is rotated again in the fastening direction. It is not necessary, and there is no fear that the nut will bite into the thread groove at an angle, so that the operability of the nut does not deteriorate. In addition, according to the present invention, the shaft is formed so as to crush the screw thread at one end of the screw shaft portion without performing a pre-processing to form a recess or a cylindrical hole on the end surface of the screw shaft portion at one end of the bolt on the loosening and moving direction side. Since the bulging head for nut removal prevention is integrally formed by pressurizing in the direction of the heart, not only the cost for the pre-processing can be omitted, it can be implemented at low cost, but also it is relaxed with a powerful rotational force today The nut that rotates in the direction can be reliably received without reducing the diameter of the bulging head for retaining the nut, thereby preventing the nut from coming off. That is, according to the present invention, even when the nut is tightened and loosened with an impact wrench, a practical bolt and nut that does not cause any inconvenience can be obtained.

  According to the bolt machining method of the present invention as set forth in claim 2, the screw shaft is fitted into the screw groove and clamped in a state in which relative movement in the axial direction is impossible in a general easy-to-use press machine. The bolt and nut according to the first aspect of the present invention can be manufactured relatively simply and easily only by combining the part clamps.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A specific embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a conventionally known pipe clamp unit 1 in which the bolt and nut of the present invention can be used. 2, a pressing member 3, a fastening bolt 4, and a nut 5. The holding member 3 is pivotally supported by a support shaft 6 at one end rising portion of the base member 2, and the free end portion of the holding member 3 is provided with a notch into which a fastening bolt 4 is detachably fitted. A bifurcated arm portion 3a is provided, and the fastening bolt 4 is pivotally supported on the other end portion of the base member 2 by a support shaft 7 parallel to the support shaft 6. A nut 5 is screwed from the end side.

  Thus, the fastening bolt 4 in a state in which the nut 5 is moved to the bolt free end side with the steel pipe sandwiched between the base member 2 and the pressing member 3 is attached to the bifurcated arm portion 3 a of the pressing member 3. The base member 2 and the pressing member 3 are closed and the nut 6 is tightened to press the pressing member 3 toward the base member 2 in this state. This pipe clamp simple substance 1 can be fixed to the steel pipe between. This pipe clamp single unit 1 is used as a pipe clamp for joining two steel pipes together by, for example, connecting base members 2 of two pipe clamp single units 1 back to back and connecting them together with bolts and nuts, etc. The base member 2 is attached to various attachment members attached to a scaffold or the like, and is used as a pipe clamp or the like for attaching various attachment members to a steel pipe constituting a temporary scaffold or the like.

  The bolt and nut according to the present invention can be used as, for example, the fastening bolt 4 and the nut 5 in the pipe clamp unit 1 described above. An embodiment of the processing method will be described with reference to FIG. 4A is one in which a bearing portion 9 having a through hole 9a through which the support shaft 7 is inserted is integrally formed at one end of the screw shaft portion 8, and the screw shaft portion 8 extends to the other end, that is, the free end 8a. A thread groove is formed over the entire length, and the nut 5 is screwed in advance from the free end 8 a of the screw shaft portion 8.

  This processing method uses a general press machine, and a pre-processing bolt 4A in which a screwed nut 5 is rotated in advance in a fastening direction to an appropriate position close to the bearing portion 9 is the screw shaft portion. The free end 8a is clamped by the screw shaft clamp 11 so that the free end 8a is located concentrically below the press die (hammer) 10. The screw shaft clamp 11 is attached to a press machine as a work holding means. The screw shaft portion free end of the nut 5 and the screw shaft portion free end of the screw shaft portion 8 of the pre-processing bolt 4A are close to the bearing portion 9. The screw shaft portion 8 is sandwiched between the screw shaft portion 8 and a region A that forms the bulging head for retaining the nut from the screw shaft free end 8a. Each clamp unit 11 a that is divided into two and freely movable for fastening is provided with an internal thread surface 11 b that fits into the thread groove of the screw shaft unit 8. The pre-processing bolt 4A sandwiched by the screw 8 is fixed at a fixed position in a state where it cannot move in the axial direction by fitting the screw groove of the screw shaft portion 8 and the female screw surface 11b of each clamp unit 11. Become. At this time, the other end of the screw shaft portion 8 of the pre-processing bolt 4A, that is, the bearing portion 9 is not supported by the support surface (lower die) as in normal press working.

  When the pre-processing bolt 4A is set as described above, the press die (hammer) 10 is operated, and the screw shaft free end 8a is pressurized in the axial direction with a predetermined applied pressure, so that the inside of the region A The screw shaft portion 8b, i.e., the screw shaft portion 8b protruding from the screw shaft portion clamp 11, is compressed in the axial direction to crush the screw groove, thereby forming a bulging head 12 for retaining the nut having a predetermined outer diameter. be able to.

  When the bolts and nuts processed by the above-described processing method are used for the fastening bolts 4 and nuts 5 of the pipe clamp unit 1 shown in FIG. 1, the nuts 5 are at the end positions in the loosening direction, that is, the bulging heads for nut removal prevention. Even when the nut 5 is rotated and moved in the fastening direction by an impact wrench in order to attach the pipe clamp unit 1 to the steel pipe because the pipe clamp unit 1 is attached to the steel pipe even in a state adjacent to the screw shaft 8, There is no inconvenience that the nut 5 does not screw well into the thread groove. Then, in order to remove the pipe clamp unit 1 from the steel pipe, when the nut 5 in the fastening operation position for fastening the pressing member 3 is rotationally moved by the impact wrench in the loosening direction, the nut 5 is temporarily attached to the bulging head 12 for retaining the nut. Even if the nut 12 is rotated and moved to the end position where it comes into pressure contact, the nut retaining bulging head 12 is integrally formed by compressing the screw shaft portion 8b in the axial direction. Therefore, if the female thread portion of the nut 5 does not bite into the nut retaining bulging head 12, the nut retaining bulging head 12 that has received the nut 5 is deformed outward. There is no fear of diameter reduction. Of course, as a result of the formation of the bulging head 12 for retaining the nut, the screw shaft portion 8 is buckled or the screw groove is deformed, and the smooth rotational movement of the nut 5 is hindered. The nut 5 can be smoothly rotated in the fastening direction and the loosening direction.

  The bolt and nut of the present invention is not only usable as the fastening bolt 4 and nut 5 of the pipe clamp unit 1 shown in FIG. 1, but the bolt whose head equivalent end is attached to the device side and the bolt If it is a bolt nut which is screwed from the free end side to the nut and does not need to be removed from the bolt, the application is not limited.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the pipe clamp single-piece | unit which can incorporate the volt | bolt nut of this invention, Comprising: A figure is a side view, B figure is a front view, C figure is a vertical side view. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the bolt nut of this invention, and its processing method, Comprising: A figure is a side view of the bolt nut of this invention, B figure is a partially vertical side view which shows the state before clamp | tightening of a bolt nut, C figure is It is a partial longitudinal cross-sectional side view which shows the state immediately before the press work of the clamped bolt nut.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pipe clamp single-piece | unit 2 Base member 3 Holding member 4 Fastening bolt 4A Pre-processing bolt 5 Nut 8 Screw shaft part 8a Screw shaft part free end 8b Screw shaft part 9 compressed in an axial direction 9 Bearing part 10 Press die (hammer )
DESCRIPTION OF SYMBOLS 11 Screw shaft part clamp 11a Clamp single-piece | unit 11b Female thread surface 12 The bulging head A for nut removal prevention A area | region which forms the bulging head for nut removal prevention

Claims (2)

  A bolt in which a nut is screwed from one end of a screw shaft portion, and an axial center so that a screw thread of the screw shaft portion is crushed at one end of the screw shaft portion without performing pre-processing on the end surface of the screw shaft portion. Bolts and nuts that are formed by integrally forming a bulging head for retaining nuts by pressurizing in the direction.   The screw shaft portion of the bolt in which the nut is screwed from one end of the screw shaft portion is separated from the one end of the screw shaft portion by an area that forms the bulging head for retaining the nut, and is fitted into the screw groove to be the shaft center. Screw in the region by holding one end of the screw shaft portion in the axial direction without holding the other end of the screw shaft portion. A bolt machining method, wherein the shaft portion is compressed in the axial direction to integrally form a bulging head for nut removal prevention.

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