JP2013096464A - Bolt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bolt which applies required fastening torque by a smaller force, in a screw fastening body using a pitch difference for fastening.SOLUTION: This bolt having a main screw threaded at a screw tip side and a sub-screw of a pitch smaller than that of the main screw threaded at a head part side. When an outer diameter of the sub-screw part of the bolt is the same as, smaller, or larger than an outer diameter of the main screw part, a nut threadedly engaging with the sub-screw part of the bolt is threadedly inserted from the head part side of the bolt where an outer diameter of a head part is smaller than the diameter of a bottom part of a screw of the nut, and the nut is locked by the main screw or a cylindrical part on the main screw side end of the sub-screw of the bolt.

Description

  The present invention relates to a bolt constituting a screw fastening body. Specifically, it is a bolt that constitutes a screw fastening body that is tightened using a pitch difference, and when tightening to a necessary tightening force using a tightening tool, the force to turn the tightening tool is reduced and tightening is performed. It relates to bolts that can be easily checked for presence or absence.

  As a technique related to the tightening torque, for example, an engaging portion with which a tightening tool is engaged in a tightening direction, a screw portion, and between the engaging portion and the screw portion, the tightening tool In a bolt with a torque limiter that prevents transmission of torque from the tightening tool to the screw portion when a torque larger than a predetermined regulation value is applied between the screw portion and the screw portion, so that no further tightening can be performed. When a torque larger than the regulation value is applied between the tightening tool and the threaded portion of the torque limiter portion, the engagement portion and the tightening tool are disengaged and the tightening tool A technique is disclosed that elastically deforms so as to idle. (For example, see Patent Document 1).

JP 2000-240627 A

  Many pipes are installed in ships, factories and the like, and in particular in ships, many pipe flanges are assembled by bolt fastening. Thus, when performing a large number of bolt fastening operations, there is a demand for a fastening structure that is easy and can be confirmed that the bolts are tightened easily.

  As a technique related to the tightening torque, the technique of Patent Document 1 is a technique that regulates the upper limit of the rotational torque at the time of tightening, but it is not a technique that reduces the force of turning using a tightening tool. When a large number of relatively large bolts are tightened as in the construction, there is a problem that a large labor is required and the burden on the operator is large. The need for such a large amount of labor also has the problem of hindering the advancement of women in other industries as women advance into the field.

  In the invention described in Patent Document 1, it is possible to prevent a torque larger than the regulation value from being applied to the threaded portion, but in order to confirm whether the torque is tightened with the regulation value torque, a torque check must be performed after tightening. As a result, it was time consuming to check the bolts one by one, making it impossible to thoroughly check the bolts.

  Assuming that conventional torque shear bolts that can be easily checked for fastening can be broken manually, the nut must be fixed with one tool and the pin tail rotated to the left (usually in the return direction) to break. Therefore, it is extremely difficult to work and it is normal to use a dedicated electric tool.Therefore, there is a problem that a torque shear bolt used by a hand-operated tool in a low tightening area such as for flange tightening has not been put to practical use. there were.

  Accordingly, an object of the present invention is a screw fastening body that is fastened by using a pitch difference, and has reduced the force of turning using a fastening tool in order to fasten a member to be fastened with a required fastening torque. The purpose of the present invention is to provide a bolt that can be tightened with force and can be easily confirmed whether it is tightened with a specified torque.

  In order to solve the above-described problem, in the bolt 2 according to the first aspect, the main screw 6 is screwed on the screw tip side, and the sub screw 7 having a smaller pitch than the main screw 6 is screwed on the head 8 side. The engraved bolt 2 is screwed into the auxiliary screw 7 portion of the bolt 2, including the case where the outer diameter of the auxiliary screw 7 portion of the bolt 2 is the same as the outer diameter of the main screw 6 portion, or when the outer diameter is small or large. The nut to be joined is screwed in from the head 8 side of the bolt 2 formed so that the outer diameter of the head 8 is equal to or smaller than the diameter of the bottom of the thread of the nut, and the auxiliary screw 7 of the bolt 2 It is characterized by being locked by the main screw 6 or the cylindrical portion 11 at the end of the main screw 6 side.

  The invention of the bolt 2 according to claim 2 is the bolt 2 in which the main screw 6 is screwed on the screw tip side, and the auxiliary screw 7 having a smaller pitch than the main screw 6 is screwed on the head 8 side. Then, a groove 10 is provided around the outer peripheral surface between the head 8 and the auxiliary screw 7, and the outer diameter of the bottom of the groove 10 is such that the shaft of the bottom of the groove 10 can be broken at a predetermined torque. A nut that engages with the auxiliary screw 7 portion of the bolt 2, including the case where the outer diameter of the auxiliary screw 7 portion of the bolt 2 is the same as the outer diameter of the main screw 6 portion, and when the outer diameter is small or large Is screwed in from the head 8 side of the bolt 2 formed so that the outer diameter of the head 8 is equal to or smaller than the diameter of the valley bottom of the screw of the nut, and the main screw 6 of the auxiliary screw 7 of the bolt 2. The side end is locked by the main screw 6 or the cylindrical portion 11.

  In the invention of the screw fastening body 1 according to the first aspect, the substantial pitch difference between the bolts 2 is smaller than the pitch of the ordinary bolts 2. For example, the main screw 6 is M12 × 1.75, and the secondary screw 7 When the pitch is 1.5, the pitch difference is 0.25, which is 1/7 compared to the pitch 1.75. During the final tightening, only the bolt 2 is rotated and the nut is in contact with the fastened member 5 Since no friction is caused by the tightening rotation with the fastened member 5 during the final tightening, the rotational torque required for the tightening can be reduced to about 70% compared to the conventional case. .

  For example, the strength classification used for fastening the ship's piping is 4.8, and the tightening torque of the M16 × 2 pitch bolt is about 100 Nm. Since a rotational torque of about 70 Nm in pitch is sufficient, the rotational torque required for tightening can be reduced by about 30%. With this rotational torque, women can be easily tightened, and women can advance into such work.

  In addition, during maintenance, in addition to being able to remove the nut to both the main screw 6 side and the head 8 side, the thread of the bolt 2 protruding from the head 8 side nut is limited to about 1 to 2 threads. Therefore, the possibility that the rust or paint or the like will not rotate will be remarkably reduced, and the work efficiency of removing the bolt 22, which is the most difficult and troublesome work in the past, will be improved, and the maintenance cost can be reduced.

  At the time of temporary tightening, the nut is rotated together with the bolt 2, and the nut is brought into contact with the fastened member 5 to complete the temporary tightening, but at the time of temporary tightening, the nut is not rotated with a strong force, so that the surface of the fastened member 5 is scratched. Not stick. Since the bolt 2 is rotated during the final tightening but the nut is not rotated, the surface of the fastened member 5 is not worn and is not damaged even if reuse is repeated during maintenance.

  The invention according to claim 2 has the same effect as the invention according to claim 1. Further, in order to obtain a torque shear type, an annular groove 10 is provided in the lower part of the neck of the bolt head 8, and the bolt head 8 is broken and separated with a certain tightening force which is a necessary torque, thereby separating the bolt head. Only by visually confirming whether or not 8 is present, it can be confirmed whether or not it is tightened with a specified tightening torque. Therefore, for example, the flange portion of the pipe is fastened with at least four bolts 2, but after fastening, the tightening result can be easily obtained simply by walking while looking at all the bolts 2 tightened by a third party. There is an effect that can be confirmed.

It is a schematic diagram of the volt | bolt (without a groove | channel) which has a cylindrical part of this invention. It is a schematic diagram of the volt | bolt which has the cylindrical part of this invention and formed the groove | channel. It is a schematic diagram of a bolt (no groove) without a cylindrical part of the present invention. It is a volt | bolt shown in FIG. 1, Comprising: It is a plane schematic diagram of the bolt head of a 12-point serration. It is a schematic diagram of the bolt which has a hexagonal hole in the head. It is a volt | bolt shown in FIG. 5, Comprising: It is a plane schematic diagram of the bolt head which has a hexagonal hole. It is the schematic of the state which made the bolt for this invention which has a groove | channel latch the subscrew nut. It is a schematic diagram of the state which made the bolt (no groove | channel) of this invention latch the subscrew nut. It is use explanatory drawing of the volt | bolt of this invention of the state which fastened the to-be-fastened member in which the screw was engraved. It is use explanatory drawing of the volt | bolt of this invention of the state which fastened the to-be-fastened member which has a bolt through-hole. (A) is a conceptual diagram in the case of the screw fastening body which consists of a normal volt | bolt nut, (b) is a fastening condition conceptual diagram. (A) is a conceptual diagram of a screw fastening body using a bolt according to the present invention when a secondary screw is screwed into a bolt, and (B) is a present invention in which a main screw and a secondary screw are screwed into a bolt. It is a fastening state conceptual diagram of a screw conclusion object using a certain bolt.

  A bolt 2 according to the present invention will be described with reference to FIGS. The bolt 2 according to the present invention is a bolt 2 in which a main screw 6 is threaded on the screw tip side and a sub screw 7 having a smaller pitch than the main screw 6 is threaded on the head 8 side. When the outer diameter of the secondary screw 7 part is the same as the outer diameter of the main screw 6 part, the nut screwed into the secondary screw 7 part of the bolt 2 includes the outer diameter of the head 8, whether it is small or large. Is screwed in from the head 8 side of the bolt 2 formed in a size equal to or less than the diameter of the bottom of the valley of the screw of the nut, and the main screw 6 or the cylinder at the main screw 6 side end of the sub screw 7 of the bolt 2. It consists of the form latched by the part 11. FIG.

  The outer diameter of the auxiliary screw 7 of the bolt 2 and the outer diameter of the main screw 6 may be such that the nut is locked at the end of the auxiliary screw 7, and the outer diameter of the auxiliary screw 7 of the bolt 2 is the outer diameter of the main screw 6. It may be slightly larger or smaller than the diameter, or the same.

  Further, when the outer diameter of the secondary screw 7 of the bolt 2 is the same as the outer diameter of the main screw 6, a nut is screwed in from the head 8, so that the outer diameter portion of the head 8 of the bolt 2 is Although there may be a form in which a thread groove (not shown) exists, there is no practical problem. Even when the outer diameter of the bolt head 8 is made larger than the diameter of the top of the thread of the sub screw nut 4 and smaller than the diameter of the valley bottom, the bolt head 8 has a thread groove. Absent.

  As shown in FIG. 3, the main screw 6 portion and the sub screw 7 portion of the bolt 2 are adjacent to each other. Thus, the respective thread grooves of the main screw 6 and the sub screw 7 may be made to communicate with each other, or may be made discontinuous without making the thread grooves communicate. Alternatively, as shown in FIG. 1, FIG. 2, or FIG. 5, a non-threaded portion such as the cylindrical portion 11 may be provided between the main screw 6 portion and the sub screw 7 portion so as to be separated from each other.

  The pitch difference between the main screw 6 and the sub screw 7 or the non-threaded portion serves as a deterrent to the rotation of the sub screw nut 4, and the free rotation of the sub screw nut 4 as shown in FIG. 7 or FIG. Can be restrained.

  As shown in FIG. 9 or FIG. 10, in the screw tightened state, if the sub screw nut 4 or the main screw nut 3 is loosened, the screw fastening body 1 made of a bolt nut can be removed. If the number of screw threads of the bolt 2 protruding from the nut on the 6 side is set to 1 to 2 threads, even if rust or paint bites into the bolt nut portion, one of the nuts is easy to loosen.

  In the temporary tightening stage, the main screw nut 3 and the sub screw nut 4 are temporarily tightened, and then final tightening is performed. In this way, only the bolt 2 is rotated in the tightening operation in the final tightening stage, and the nut that comes into contact with the fastened member 5 does not rotate at this time. Even if the loosening and tightening are repeated, there is an effect that the surface of the fastened member 5 is hardly worn.

  Since the bolt 2 does not have a head seating surface, only the bolt 2 without the seating surface is rotated when the final tightening is performed, and the nut is not rotated. Therefore, friction with the fastened member 5 does not occur. The final tightening can be done with a tightening force of about 30% reduction. As a result, when a large number of bolts and nuts are continuously tightened, fatigue is less likely to occur, and a person with weaker tightening force than before can also perform the tightening operation.

  Since the nuts on the main screw 6 side and the sub screw 7 side may be commercially available, there is an effect that the nut can be easily spread to the market as compared with the case where the nut is special.

  Further, the bolt 2 is provided with a groove 10 on the outer peripheral surface between the head 8 of the bolt 2 and the auxiliary screw 7 so that the shaft at the bottom of the groove 10 can be broken with a predetermined torque. The outer diameter part of the bottom of the groove 10 is formed.

  Since the breaking of the groove 10 occurs when a certain torque is applied, the bolts 2 are tightened until the breaking, whereby all the screw fastening bodies 1 using the bolts 2 of the present invention are fixed. It can be tightened with torque. As a result, it is possible to eliminate the tightening failure, which is said to account for about 43% of the tightening troubles, and it requires skill to be able to tighten the conventional bolts and nuts with the specified tightening torque. Then, there was a big difference in tightening torque variation, but there was no difference between skilled and unskilled workers, and even newcomers were able to leave the tightening work with peace of mind.

  Further, since the bolt head portion 8 of the screw fastening body 1 after tightening is not detached due to the fracture of the groove 10 portion when the specified tightening torque is reached, the operator himself can perform the tightening operation. It is possible to confirm whether the tightening torque has reached the specified value for each of the two bolts. After the operator completes the tightening operation, the construction manager etc. walks around the work site in the ship and walks visually. Only by checking, there is an effect that it is possible to easily check whether each screw fastening body 1 is tightened with a specified tightening torque.

  And the shape of the tool hanging portion of the head 8 of the bolt 2, for example, a hexagonal shape, or a 12 point serration 13 as shown in FIG. 4 or a shape in which a tool such as a hexagonal hole 12 does not slip as shown in FIG. 6. If it is.

  Next, the screw fastening body 1 using the bolt 2 of the present invention will be described.

  When the screw is screwed into the bolt 2 insertion hole of the fastened member 5, the screw fastened body 1 is configured without a nut on the main screw 6 side as shown in FIG. 9. When the screw is not screwed into the bolt insertion hole, the fastened member 5 is sandwiched between the main screw nut 3 and the sub screw nut 4 as shown in FIG.

  Here, in FIG. 9, the bolt 2 in a state in which the secondary screw 7 side nut is screwed is screwed into the member to be fastened 5, temporarily tightened with the secondary screw nut 4, and then the bolt 2 is finally tightened. As it goes on, the bolt 2 advances in the screwing direction with respect to the nut.

  The main screw 6 and the auxiliary screw 7 of the bolt 2 have a head 8, a shaft formed by molding the main screw 6 and the auxiliary screw 7, the shape of the main head 8, It can be manufactured by rolling with a rolling die in which the screw 6 and the auxiliary screw 7 are separately or integrally engraved, and no special manufacturing method is required. At this time, the outer diameter and pitch of the auxiliary screw 7 and the main screw 6 are set to match the commercially available nut. In addition, when using for a special use, it is not limited to a commercially available nut.

  The use of the screw fastening body 1 using the bolt 2 according to the embodiment of the present invention will be described in the case of the form of FIG. 9 and / or FIG.

  In the screw fastening body 1 using the bolt 2 according to the embodiment of the present invention, the first screw body having the same outer diameter of the main screw 6 and the auxiliary screw 7 or the outer diameter of the auxiliary screw 7 is changed to the main screw 6. In the second configuration slightly larger or smaller than the outer diameter of the first, or the first or second configuration, as shown in FIG. 1 or FIG. There is a form in which the non-threaded portion is provided, and a form in which the main screw 6 and the sub screw 7 are adjacent to each other as shown in FIG. Since both can be locked at the end of the auxiliary screw 7, the auxiliary screw 7 side nut can be locked to the bolt 2 before screwing into the fastened member 5.

  A case of using the main screw nut 3 shown in FIG. 10 will be described. First, the sub screw nut 4 is completely screwed into the sub screw 7 of the bolt 2, and the nut is locked at the end of the sub screw 7.

  When the main screw 6 and the sub screw 7 are separated from each other, for example, a cylindrical portion 11 may be provided at an intermediate portion thereof. In this case, the cylindrical portion 11 locks the nut at the end of the cylindrical portion 11.

  Then, the main screw 6 nut 3 is screwed in from the screw tip side of the bolt 2 while the bolt 2 to which the sub screw nut 4 is screwed is inserted into the hole of the fastened member 5. The nut 6 for 6 and the nut 4 for the auxiliary screw 7 are brought into contact with the surface of the fastened member 5 and further temporarily tightened.

  Next, when the bolt 2 is tightened, the final tightening starts. If a tool is put on the bolt head 8 and tightened, the main screw 6 and the sub screw 7 are tightened simultaneously, and the main screw 6 and the sub screw 7 are to be screwed in at a pitch difference. And the screw contact surface of the sub screw nut 4 and the screw contact surface of the main screw 6 and the main screw nut 3 cause a large frictional resistance, and a large compressive force is generated, so that the bolt 2, the nut, and the fastened member 5 are Fixed.

  Next, the screwing situation will be described with reference to the conceptual diagram of the bolt and nut combination of the present invention. First, the case of a normal bolt and nut for comparison will be described with reference to FIG. FIG. 11 (a) is a conceptual diagram of tightening with ordinary bolts and nuts 22 and 23, and FIG. 11 (b) is an explanatory view of a screwing situation.

  In FIG. 11 (b), the underline b in the horizontal direction indicates the surface to be fastened of the member 5 to be fastened, the upper line a indicates the size of the pitch of the bolts 22 and nuts 23 by the lead angle, and the wedge sandwiched between the upper and lower lines. The body 40 shows the thread and the bearing surface of the main screw 29 of the nut 23.

  FIG. 11B shows a configuration in which the normal nut 23 is pushed into the main screw portion of the bolt 22 while abutting against the surface of the fastened member 5.

  Next, the case of the present invention is shown in FIGS. 12 (a) and 12 (b), in which the female screw of the main screw is engraved on the fastened member 5 and there is no main screw nut. . FIG. 12 (a) shows a conceptual diagram when the auxiliary screw 7 is screwed into the bolt 2. FIG. 12 (b) is a conceptual diagram of the fastening state of FIG. 12 (a).

  12 (b), the upper groove-like body 26 represents the thread groove of the sub screw 33 of the nut 4, and the lower groove-like body 27 represents the thread groove of the main screw of the member 5 to be fastened. The pitch is expressed by the inclination of the groove 27, and the pitch of the auxiliary screw is expressed by the inclination of the groove 26. The substantially U-shaped wedge body 41 represents the bolt 2, the upper portion of the wedge body 41 represents the thread of the auxiliary screw 7, and the lower portion represents the thread of the main screw 6.

  The shape in which the wedge body 41, which is the bolt 2, is pushed into the grooves with different slopes of the main screw 35 of the fastened member 5 and the sub screw 33 of the nut 4 shown in FIG. The bolt 2 is pushed into the groove 26 and the groove 27.

  Next, the present invention will be described with examples of use.

[Usage example 1]
This is the case of the bolt 2 shown in FIG. 1, wherein the main screw 6 of the bolt 2 is 5/8 inch and the pitch is about 2.3 mm, the auxiliary screw 7 is M16 and the pitch is 2 mm, and the pitch difference is about 0.3 mm. In this case, the turning force when using the tightening tool was 70 Nm.

  As a comparative example, when the main screw 6 of the bolt 2 was M16 and the pitch was 2 mm, the turning force when using a tightening tool was about 100 Nm. As a result, the use of the bolt 2 of the present invention has an effect that the force to be turned when the tightening tool is used may be about 70%.

1 Screw Fastening Body 2 Bolt 3 Main Screw Nut 4 Sub Screw Nut 5 Fastened Member 6 Main Screw 7 Sub Screw 8 Head 10 Groove 11 Cylindrical Part 12 Hexagonal Hole 13 12 Point Serration 22 Bolt (Normal Bolt)
23 Nut (Normal nut)
26 Groove 27 Groove 29 Main Screw (Nut)
33 Sub screw 35 Main screw 40 Wedge body 41 Wedge body a Upper line b Underline

Claims (2)

  A bolt in which the main screw is threaded on the screw tip side and a sub screw having a smaller pitch than the main screw is threaded on the head side, and the outer diameter of the sub screw portion of the bolt is the outer diameter of the main screw portion. In the case where the nut is screwed into the auxiliary screw portion of the bolt, including the case where it is the same as or smaller than the bolt, the bolt is formed such that the outer diameter of the head is equal to or smaller than the diameter of the valley bottom portion of the screw of the nut. The bolt is screwed in from the head side of the bolt and is locked by the main screw or the cylindrical portion at the main screw side end of the auxiliary screw of the bolt.   A bolt in which a main screw is threaded on the screw tip side and a sub screw having a smaller pitch than the main screw is threaded on the head side, and a groove is formed on the outer peripheral surface between the head and the sub screw. An outer diameter portion of the bottom portion of the groove is formed so that the shaft of the bottom portion of the groove can be broken at a predetermined torque, and the outer diameter of the auxiliary screw portion of the bolt is equal to the outer diameter of the main screw portion. In the same case, including the case where the bolt is small or large, the nut screwed into the auxiliary screw portion of the bolt has an outer diameter of the head formed to be smaller than the diameter of the valley bottom portion of the screw of the nut. A bolt which is screwed in from the head side and is locked by a main screw or a cylindrical portion at a main screw side end of the auxiliary screw of the bolt.

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