JPH0222490Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a nut loosening device that prevents a nut screwed into a bolt from rotating loosely due to slight vibrations from the outside.

[Background technology of the invention]

Generally, the live parts of electrical equipment are covered with an insulating material to prevent accidents such as electric shock.This insulating material is used to insulate the equipment from the viewpoint of ease of inspection of the live part and safety. It was attached using body bolts and nuts. for example,
As shown in Utility Model Application Publication No. 57-20021,
In a resin molded transformer, as shown in Fig. 4, the outlet terminals 3, 3', intermediate tap terminals 4, and relay terminals 5 protruding from the outer surface of each phase coil 2 attached to the iron core 1 are insulated. By covering the molded transformer A with the body cover plates 6, 6', various problems arise due to the live parts of the molded transformer A being exposed to the outside (for example, when installing the transformer A, other This prevents the equipment from colliding with the outlet terminal 3, etc., causing cracks in the resin insulation layer at its base, electric shock accidents, etc.). When installing the cover plates 6, 6', as shown in FIGS.
A pair of vertically elongated cover plates 6, 6' formed in a letter shape,
As shown in FIG. 5, these cover plates 6,
Pass the mounting seat 7 between 6' and insert the synthetic resin bolt 8.
was inserted, and a nut 9 also made of resin was screwed onto this bolt 8 to attach the cover plates 6, 6' to the mounting seat 7. Further, an interphase connection conductor 10a for connecting each phase coil 2 is passed through an insulating tube 10 located below and perpendicular to the cover plates 6, 6'. A cover plate 6 is inserted into the horizontal hole 11 opened to
Insert the output terminal 3' that has passed through the insulating tube 10, and connect the output terminal 3' and the interphase connection conductor 10a to each other using the operation hole 12 opened at the bottom of the insulating tube 10, as shown in FIG. By connecting the members with set screws 13, the insulating cylinder 10 is held by the cover plates 6, 6' so as not to fall off.

[Problems in the Background Art] However, the bolts 8 and nuts 9 for fixing the cover plates 6, 6' to the mounting seat 7 are necessary because the cover plates 6, 6' are fixed near the live parts of the transformer A. , is made of an insulating material (synthetic resin). Therefore, when the nut 9 is screwed onto the bolt 8 and tightened strongly, the threads of the bolt 8 or the nut 9 are soft unlike metal, so the nut 9 will be crushed. There were cases where it became impossible to tighten. Therefore, the nut 9 was only tightened to the extent that the threads were not crushed. However, vibrations of the iron core 1 that occur during operation of the transformer are transmitted to the bolts 8 and nuts 9 through the coil 2, causing the nuts 9 to loosen, or sometimes the nuts 9 to loosen too much, causing the bolts 8 to loosen.
There was a risk that the cover plate 6' would become unscrewed and fall off the mounting seat 7, exposing live parts such as the outlet terminal 3 on the outer surface of the coil 2 to the outside. For this reason,
In order to prevent the nut 9 from loosening, it is possible to fix the nut 9 and the bolt 8 with adhesive, or to fix the cover plates 6, 6' directly to the mounting seat 7 with adhesive, etc., but these methods None of these methods could be adopted because the cover plate 6' could not be removed from the mounting seat 7 when inspecting the live parts.

[Purpose of invention]

The present invention is a nut loosening device that eliminates the above-mentioned drawbacks and prevents a nut made of the same material as a bolt screwed into a synthetic resin bolt from idling or falling off due to slight external vibrations. Our goal is to provide the following.

[Summary of the idea]

In the locking device of the present invention, a locking member with excellent wear resistance installed inside a nut is engaged within a one pitch range with a thread groove of a bolt that is screwed into the nut, and this locking member is attached to the bolt. This prevents the nut from loosening by being locked in the thread groove of the nut.

[Example of idea]

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, FIG. 2, and FIG. 6, the same parts as in the conventional example are given the same reference numerals and explained.
In FIG. 1, the nut 90 has a concave groove 15 concentric with the thread of the nut 90 in the center of its inner peripheral surface. Excision part 1 where a ring-shaped part is removed using synthetic resin with excellent elasticity
As shown in FIG. 1, a locking member 16 formed into a C-shape with a portion 6a is loosely fitted. The locking member 16 has a thickness such that it can be engaged with the thread groove 8a of the bolt 8 within a one-pitch range, and the diameter of its inner peripheral surface is such that it cannot be pulled out from the thread groove 8a. In other words, the diameter of the thread groove 8a of the bolt 8 is equal to or slightly larger than the diameter of the thread groove 8a of the bolt 8. Also, the groove 15
As shown in FIG. 6, a protrusion 17 that fits loosely with the cutout 16a of the locking member 16 is provided on a part of the inner part with a length that does not protrude from the root diameter of the thread groove 9a of the nut 90. has been done. Next, the nut 90 provided with the locking member 16 is screwed onto the protruding end of the bolt 8 protruding from the cover plate 6', and the nut 90 is sequentially screwed into the bolt 8.
The C-shaped locking member 16 loosely fitted into the bolt 8
When reaching the position of the thread groove 8a at the tip, the locking member 16 is engaged with the thread groove 8a at the tip of the bolt 8 by screwing the nut 90.
Due to the screwing action, the concave groove 15 of the nut 90
The protrusion 17 protruding inwardly contacts one end of the cutout 16a of the locking member 16, causing the locking member 16 to move along the thread groove 8a of the bolt 8 in conjunction with the nut 90 to tighten the cover plate 6. ’ side sequentially. When the nut 90 comes into contact with the cover plate 6' as shown in FIG. 1, the tightening of the nut 90 is completed. At this time, the loosening member 16 is
One end of the bolt 6a comes into contact with the protrusion 17 and engages within a one-pitch range with the thread groove 8a of the bolt 8, so that it is independently locked in the thread groove 8a.

When a slight vibration is applied to the nut 90 from the outside in this state, the nut 90 tries to rotate freely, but the protrusion 17 of the nut 90 is received by the other end of the cutout 16a of the locking member 16 and is prevented, and the nut 90 is rotated freely. 90 from idling, and the locking member 1
When a part of the nut 90 comes into contact with the inner circumferential surface of the groove 15, the nut 90 is stopped at that part and the nut 90 is prevented from rotating freely. Next, when removing the nut 90 from the bolt 8, the nut 90 locks the locking member 16 onto the bolt 8 using the protrusion 17 protruding into the groove 15 by performing the operation opposite to that used when tightening the nut 90. Remove it from the bolt 8 while rotating it along the thread groove 8a in the opposite direction to the tightening direction.

When the nut 90 is removed from the bolt 8, the locking member 16 is loosely fitted into the groove 15 in the nut 90, so that it will not fall off from the nut 90.
Further, the locking member 16 is formed in a C-shape, and the protrusion 17 in the groove 15 comes into contact with the cutout 16a of the locking member 16, and as the nut 90 rotates, the locking member 16 is moved along the thread groove 8a of the bolt 8. When the nut 90 is tightened or removed, the locking member 16 is attached to the thread 8 of the bolt 8.
There is no possibility that the nut 90 will become unsmooth in rotation due to the nut 90 getting stuck in the thread groove 9a of the nut 90.

The inner circumferential surface of the locking member 16 may be formed into a blade shape to facilitate fitting into the thread groove 8a of the bolt 8.

FIG. 7 shows another embodiment of the present invention, the structure of which is, for example, as shown in FIG.
A fine hole 92 is bored horizontally from the circumferential surface of the bolt 8 toward the thread groove of the bolt 8, and a locking member 93 formed in a rod shape made of synthetic resin is inserted into the fine hole 92, as shown in FIG. It is inserted so as to be able to engage with the screw groove 8a, and then an adhesive or the like is applied to the opening of the pore 92 to prevent the locking member 93 from coming off. When the nut 91 with the locking member 93 attached in this manner is screwed into the bolt 8, the locking member 93
As shown in FIG. 7, the nut 91 is engaged with a portion of the thread groove 8a of the bolt 8 to prevent the nut 91 from rotating freely or coming off. Moreover, since the locking member 93 is held in the small hole 92 without falling off, when the nut 91 is rotated, it can move smoothly along the thread groove 8a of the bolt 8 together with the nut 91. Because it is possible to
Rotation of the nut 91 is not hindered. Further, the locking member 93 can be easily attached by providing a hole 92 in the nut 93.

FIG. 9 shows another embodiment of the present invention, whose structure is such that a ring-shaped recessed hole 102 is provided at one end of a nut 101, and the inner peripheral surface of this recessed hole 102 is formed into a blade shape. A ring plate-shaped locking member 103 made of synthetic resin is attached to the nut 101 by fixing it with adhesive, etc., and the inner peripheral surface of the locking member 103 is cut in several places in the radial direction. A recessed portion 104 is provided. When the nut 101 is screwed into the bolt 8, the locking member 103 is tightened by the notch 104 into the thread 8b.
The nut 101 is tightened while sequentially moving along the thread groove 8a of the bolt 8 without biting into the thread groove 8a of the bolt 8. After tightening the nut 101, the locking member 103 engages with the thread groove 8a of the bolt 8. Therefore, the nut 101 will not rotate freely due to slight vibrations from the outside.

The locking member 103 has a large number of sharp protrusions 105 formed on the end surface that contacts the cover plate 6', thereby making close contact between the locking member 103 and the cover plate 6' to reduce frictional resistance at this portion. By increasing the size, free rotation of the nut 101 may be prevented.

[Effect of idea]

As explained above, according to the present invention, the C-shaped locking member is loosely fitted into the groove formed concentrically with the screw in the center of the inner peripheral surface of the nut, and is provided to protrude into the groove. The locking member is adapted to move in conjunction with the rotation of the nut by the protrusion loosely engaged with the cut-out portion of the locking member, so that when the nut is tightened onto the bolt, the locking member only tightens in the thread groove of the bolt. It is possible to engage within a one-pitch range along the bolt and lock it independently in the thread groove of the bolt, and even if the nut tries to rotate freely due to external vibrations, etc., it will not be locked independently. Since the protrusion is received at the end of the locking member, free rotation of the nut can be prevented, and the nut can be accurately prevented from loosening or coming off. In addition, since the inner circumferential surface of the locking member is formed to have a diameter that does not allow it to slip out of the thread groove of the bolt, it can be engaged only along the thread groove of the bolt by rotation of the nut. When the nut rotates, the locking member never bites into the threads of the bolt, and the locking member engages with the thread groove of the bolt and locks independently. Also, the nut can be attached and detached smoothly. Moreover, since the locking member is configured to engage with the thread groove of the bolt as the nut rotates and to be independently locked in the thread groove, the locking member can be compressed when the nut is tightened. It is possible to prevent the nut from loosening without expanding or deforming it, and even if the nut is installed and removed during periodic inspections, it prevents wear and tear on the locking member and maintains stable locking over a long period of time. can do. Further, the locking member is made of a ring-shaped C having elasticity with a part cut out.
Because it is shaped like a letter, even if the outer diameter of the nut is larger than the threaded inner diameter of the nut, the outer diameter can be compressed and compressed to reduce the outer diameter so that both ends of the cut out part come into contact with each other, allowing the nut to fit loosely into the groove. Once fitted, the member will return to its original state due to its elasticity, so even if the nut is removed from the bolt, the locking member will not fall off from the nut. Since it has a simplified structure in which a C-shaped locking member is loosely fitted, the nut can be formed without increasing its size.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway sectional view of the main part of the locking device of the present invention, FIG. 2 is a longitudinal sectional view of FIG. 1,
Figure 3 is a front view of a molded transformer showing an example in which a conventional nut is used on a cover plate that covers the live parts of the molded transformer, and Figure 4 is an enlarged view of the conventional nut used. FIG. 5 is a plan view, FIG. 6 is a longitudinal sectional view of the nut of the present invention, and FIG. 7 is a longitudinal sectional view of another embodiment of the present invention. , FIG. 8 is a sectional view taken along line A-A in FIG. 7, FIG. 9 is a longitudinal sectional view showing still another embodiment of the present invention, and FIG. 10 is a front view of the nut shown in FIG. 9. . 8... Bolt, 9, 90, 91, 101... Nut, 15... Concave groove, 16, 93, 103... Loosening member.

Claims (1)

[Scope of utility model registration request] A groove concentric with the thread of the nut is provided in the center of the inner peripheral surface of the nut made of synthetic resin, and a ring-shaped cutout portion is formed in the groove,
C made of synthetic resin with excellent abrasion resistance, whose inner circumferential surface has a diameter that prevents it from coming off within one pitch with the thread groove of the bolt that screws into the nut.
A letter-shaped locking member is loosely fitted, and a protrusion that loosely fits into the cutout of the locking member is provided in the recessed groove with a length that does not protrude beyond the root diameter of the thread of the nut, and the nut is attached to the bolt. When the nut is screwed in, the locking member cooperates with the nut through the protrusion to engage with the thread groove of the bolt, thereby independently locking the nut. Device.