JPH0241649B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a nut case that maintains constant tightening torque for bolts and nuts. In order to obtain a predetermined axial force when fastening bolts and nuts, it is necessary to tighten them with a fastening torque within a certain range. For this reason, many special fastening tools and bolt nuts with special structures have been developed to maintain a constant fastening force. However, the conventional fastening method has the following problems. <B> When using a special tool, the tool is large due to its complicated structure, and its use may be restricted depending on the surrounding circumstances. <B> When adding nuts to a single bolt, it is not possible to check the tightening force of nuts where a torque wrench cannot fit. <C> After tightening, the tightening force must be checked, and this work requires a great deal of effort, especially when there are many difficult-to-check points. <D> Even when special tools or bolts and nuts with a special structure are used, they are expensive and uneconomical. The present invention has been made to improve the above points, and an object of the present invention is to provide a nut case that makes the fastening torque constant as described below. <A> A nut case with a simple structure that allows you to check a constant fastening torque without using special tools or specially structured bolts and nuts. <B> A nut case that can be tightened with the specified torque and cannot be applied with more than the specified force. <C> A nut case that will not fall off from the nut after it is concluded. Next, an example will be described. The nut case of the present invention is fitted onto an existing nut to provide a certain level of strength to the protrusion that protrudes into the case, and the case is tightened until the protrusion breaks to ensure a predetermined tightening torque, and the case is secured to the bolt. This is intended to prevent the nut from rusting by screwing it into the threaded part. <B> Nut case As shown in Fig. 1, the nut case 1 is a tube with a cylindrical inner surface and a polygonal outer surface, one end of which is an open end 5, and the other end is provided with an annular collar 2 inscribed in the open end. A protrusion 3 is provided to protrude independently from the inner wall on the end 5 side. The outer shape of the nut case 1 is formed into a hexagonal shape, for example, but the outer shape is not limited to this, and may be formed into a square or other polygonal shape. The key is to form it into a shape that allows use of well-known spanners and wrenches. As the material constituting the nut case 1, a known material such as a synthetic resin with excellent rigidity is used. <B> Flam 2 The collar 2 is a single band-shaped plate, which is not provided in an endless manner but goes around the same slope as the bolt peak, and the two ends thereof are provided so as to form a drop 21 and a slit 22. . The reason why the collar 2 is slanted in a spiral shape is so that the inner edge of the collar 2 can be screwed into the thread of the bolt, and the slit 22 is used to give elasticity to the collar 2 and prevent the nut case 1 from spinning idly. This is to prevent the collar 2 from being damaged due to the threading of the collar 2 proceeding more than necessary, and also to allow for flexibility in dealing with bolts of different pitches. Further, since the force is not particularly concentrated on the tsuba 2, there is no need to form it with special strength, and the tsuba 2 is made of the same material as the nut case 1. <C> Projection The projection 3 has an appropriate length in the axial direction of the nut case 1, and is provided to protrude on the inner peripheral wall surface of the nut case 1 so as to prevent the nut from passing through the corner. The protrusion 3 forms a triangular column whose transverse cross section has two acute or obtuse faces that intersect, and is particularly spaced apart from the collar 2 by an appropriate distance d. The reason why the protrusion 3 is not provided in contact with the collar 2 is that if the protrusion 3 were provided in contact with the collar 2, the protrusion 3 would be reinforced and the breaking strength under the same conditions would not be obtained, and the shape of the nut would be inaccurate. This is because the fracture strength varies due to the influence of the sag. The protrusions 3 are independently arranged at equal intervals equal to or less than the number of corners of the nut (six in the drawing) so that rotational force acts uniformly on each surface of the nut. When a predetermined fastening torque is applied to the protrusion 3, the protrusion 3
Configure it so that only it is corrupted. The limit value at which the protrusions 3 are damaged is appropriately determined by the strength and number of protrusions 3 formed in accordance with the designated fastening torque. The strength of the protrusion 3 is influenced by the protrusion dimension a, the protrusion length b, the protrusion angle, the protrusion shape, and the material from which the protrusion 3 is made. The projection 3 may be formed of the same material as the nut case 1 and the collar 2, or in some cases, other known materials different from the nut case 1 and the collar 2 may be used, so that the strength of the projection 3 is determined only by the material. can be found. Next, we will explain how to use the nut case. <A> Fitting the nut case The nut case 1 having the above structure is attached to the outer periphery of the nut 4.
The open end 5 side of the nut 4 is placed in contact with the object to be fastened, and the nut 4 with the nut case 1 still fitted is attached to the bolt 5. <B> Damage to protrusions When the nut case 1 is continued to be rotated using a known spatula or wrench, the nut 4 fitted in the nut case 1 is screwed into the bolt 5 and tightens the object 6 to be fastened. When nut 4 has been threaded to a certain extent, nut 4
The torque acting on the protrusion 3 of the nut case 1 that is in contact with the corner surface of the nut case 1 increases. If the force exceeds the strength limit value of the protrusion 3, the protrusion 3 will be crushed and the corner will disappear. As a result, transmission of rotational force between the nut case 1 and the nut 4 becomes impossible, and the fastening of the nut 4 is completed. <C> Checking the tightening torque Even after the nut 4 has been tightened, the nut case 1 fitted into the nut 4 will continue to fit without coming off from the nut 4 since the collar 2 is screwed into the bolt 5. I'm wearing it. Therefore, in order to confirm whether or not the nut 4 has been tightened with a predetermined tightening force, it is sufficient to manually touch the nut case 1 directly. That is, if the nut case 1 is spinning idly, it can be easily confirmed that the nut 4 into which the nut case 1 is fitted has been tightened. <D> Other Example 1 When using a large number of nuts of different sizes, it is recommended to color the nut case 1 according to the set torque so that the color can be seen later (for example, when retightening the nut after disassembly). You can easily know the set torque of nuts and bolts with just <E> Other Embodiments 2 In the above embodiments, the case where the protrusion 3 provided in the nut case 1 is formed with acute intersecting planes has been described, but the protrusion 3 may be formed with a rectangular planar shape. In addition, a spherical protrusion 3 may be provided. <F> Other Embodiment 3 Although the above description has been made regarding the state of fitting into a nut, the same principle can also be applied to the head of a bolt. (FIG. 4) That is, by fitting the bolt case 7 similar to the above embodiment to the head 6 of the bolt, torque can be managed by the same operation. However, since the collar 8 of the bolt case 7 cannot engage with the thread, it is only necessary to engage the curved surface 9 at the lower corner of the bolt head. Since the present invention is as explained above, the following effects can be expected. <B> Since no special processing is required on the existing nut, and no special tools are required, the designed axial force can be applied to the bolt within a range that is neither too little nor too much by applying torque within a certain range. be able to. <B> There is no need to use a tool to check whether a predetermined torque has been applied after tightening the nut, and the tightened state of the nut can be checked simply by touching the nut case with your hand. <C> Since the collar formed at one end of the nut case is threaded with the bolt when the fastening is completed with a predetermined torque, the nut case maintains the state of being fitted onto the nut. Therefore, the nut case protects the nut and the threaded portion from the influence of water and dust, and can be expected to have a corrosion-proofing effect. <D> Also, even if the nut case is used facing upward, there is no need for it to fall off as described above. Therefore, even after the nut tightening work is completed, the nut case can be prevented from being scattered on the floor or other surrounding areas. <E> Since the protrusions protrude into the nut case and are formed independently at a certain distance d from the brim surface, each protrusion is not affected by reinforcement by the brim or sagging of the nut, allowing for accurate fastening. Torque can be set. <F> If the nut case is colored, it will be easy to distinguish nuts and bolts by torque setting, which will be extremely convenient during disassembly.

[Brief explanation of the drawing]

Fig. 1: An explanatory diagram of an embodiment of the nut case according to the present invention, Fig. 2: An explanatory diagram of the state of use, Fig. 3:
Explanatory diagram when the nut is fitted into the case, 4th
Figure: Explanatory diagram of another embodiment. 1: Nut case, 2: Brim, 3: Protrusion, 4:
Natsu, 7: Bolt head case.

Claims (1)

[Claims] 1. In a prismatic case with open upper and lower ends,
One end of this case has a protruding collar that engages with the thread of the bolt, and the other end has protrusions arranged at equal intervals at positions that contact the surface of the existing nut. Nut case that maintains a constant fastening torque, characterized by the fact that the protrusions are formed independently at intervals and the limit fastening torque is applied only to the protrusions.