JPS628647B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a combination nut that is engaged with a bolt to fix a member to be tightened.

Fastening of members to be tightened using bolts and nuts is currently widely used, and conventional fastening involves simply threading a nut onto a bolt and firmly pressing the end face of the nut against the surface of the member to be tightened.

However, if the end face of the nut is simply tightened to the member to be tightened in this manner, there is a risk that the screw may loosen due to vibrations after tightening, which may cause a serious accident. In order to prevent such screws from loosening, plastic or the like was wrapped around the threaded portions. However, the nut provided with such a locking means has the disadvantage that it is difficult to regenerate the nut and the nut cannot be used again. SUMMARY OF THE INVENTION In view of the above, an object of the present invention is to provide a combination nut that can completely prevent loosening, which tends to occur in conventional nuts, by a simple operation.

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

1 to 3, the combination nut M of the invention consists of a hexagonal outer lock nut 1 and an inner lock nut 2 screwed into the outer lock nut 1 and cooperating with the outer lock nut 1.

A space S 1 extending in the axial direction into which the bolt 3 is inserted is formed in the center of the outer lock nut 1, and a first space S ₁ is formed on the upper circumferential surface of this space S ₁ to be screwed into the external threaded portion 3a of the bolt 3. A female threaded portion 1a is formed. A second female threaded portion 1b having a larger effective diameter than the first female threaded portion 1a is formed on the lower circumferential surface of the space _S1 , and is connected to the first and second female threaded portions 1.
An unthreaded inner circumferential portion 1c is formed between a and 1b.

The inner lock nut 2 has a first male threaded portion 2a formed on its upper outer circumferential surface with a thread that is threaded into the second female threaded portion 1b of the outer lock nut 1, and a first male threaded portion 2a that corresponds to the outer lock nut 1 at its lower portion. A hexagonal bottom flange 2b is provided so as to
The first male threaded portion 2a and the bottom flange 2b
An unthreaded outer cylindrical portion 2c is formed therebetween.

Further, a space S ₂ extending in the axial direction through which the bolt 3 is inserted is formed in the center of the inner lock nut 2, and the external threaded portion 3a of the bolt is formed on the circumferential surface of this space S ₂ .
A third female threaded portion 2d is formed to be screwed into the outer lock nut 1, and the first female threaded portion 1a of the outer lock nut 1 and the third female thread portion 2d of the inner lock nut 2 are formed to have the same effective diameter and the same pitch. ing.

The pitch of the male threaded portion 3a of the bolt, the first female threaded portion 1a of the outer lock nut 1 that is screwed into this male threaded portion, and the third female threaded portion 2d of the inner lock nut 2 is the same as the second female thread of the outer lock nut 1. It is formed larger than the pitch of the first male threaded part 2a of the part 1b and the inner lock nut 2 screwed thereto, and for example, the first three are coarse threaded (M10 x 1.5).
The latter two are formed into fine threads (M16 x 1).

Bottom flange 2b of the inner lock nut 2
is a pressing surface _2b1 that contacts the member to be tightened 4, and extends parallel to the opposite side of this pressing surface _2b1 and contacts the lower end surface 1d of the outer lock nut 1 to extend the insertion depth of the inner lock nut 2 into the inner lock nut 1. It has a regulating surface 2b ₂ for regulating the temperature.

In addition, the above-mentioned fully threaded parts 1a, 1b, 2a, 2
Threads d and 3a are formed in the same direction, and may be formed as right-handed or left-handed threads, and all the threaded portions are formed concentrically.

Next, the operation of the present invention will be explained.

When using the combination nut M of the present invention,
First, the inner lock nut 2 is inserted into the outer nut 1 while screwing the first male thread part 2a onto the second female thread part 1b. This is done until the regulating surface 2b ₂ comes into contact (the first
figure).

After combining both nuts 1 and 2 in this state, screw the combination nut M onto the bolt 3,
The outer lock nut is rotated with a wrench to press the bottom flange pressing surface _2b1 of the inner lock nut against the member 4 to be tightened under the necessary torque.

Next, as shown in FIG. 4, the bottom flange 2b of the inner lock nut 2 is fixed with a spanner or the like, and the outer lock nut 2 is rotated with another spanner in the opposite direction to the direction in which the member 4 to be tightened is tightened. The lower end surface 1d of the outer lock nut 1 is separated from the regulating surface _2b2 of the inner lock nut.

Then, as shown in FIG. 5, the distance traveled upward due to the screw engagement between the first female threaded portion 1a and the male threaded portion 3a of the bolt is greater than the distance traveled by the second female threaded portion 1b and the first male threaded portion 3a. Since the distance is greater than the distance traveled upward due to the screw engagement with part 2a, a difference in the relative travel distance will occur due to the pitch difference between the two screw engagement parts, and the latter screw engagement will be greater than the distance traveled upward by the screw engagement with the former part. This limits the advancement of the first female threaded portion 1a of the portion. Therefore, the lower inclined surfaces i, i, i of the thread of the first female threaded portion 1a come into contact with the upper inclined surfaces j, j, j of the thread of the bolt male threaded portion 3a,
Eventually, a downward force F _A acts on the threaded portion.

On the other hand, when both the lock nuts 1 and 2 are integrally screwed onto the bolt 3 and the member to be tightened 4 is tightened, the upper sloped surfaces k, k...k of the third female threaded portion of the inner locknut are aligned with the male threaded portion of the bolt. 3a, and an upward force F _B is applied to the threaded portion.

Therefore, the downward force F _A and the upward force F _B will bite into the male threaded portion 3a of the bolt, and in this case, the combination nut M will no longer be able to rotate and will never loosen. do not have.

To loosen the fastening between the bolt and nut, rotate the outer lock nut 1 in the opposite direction to the locking state so that the lower end surface 1d of the outer lock nut 1 comes into contact with the regulating surface 2b2 of the inner lock nut ₂ , and then Both lock nuts 1 and 2 are rotated integrally in the opposite direction to the direction in which they are tightened.

Note that when locked, a gap is created between the lower end surface 1d of the outer lock nut and the regulating surface _2b2 of the inner lock nut due to the play of the threaded portion of each screwed part.
After locking, inserting a wedge W into this gap as shown in FIG. 5 will ensure that the outer lock nut 1 remains tightened.

Furthermore, the outer lock nut 1 does not have to be hexagonal, and may have a circular peripheral surface partially cut off to form a flat surface 5a for engagement with a spanner, as shown in FIG. In this case, it is preferable that the bottom flange of the inner lock nut be formed in the same shape.

In this way, if you use the difference in pitch of each threaded part of a combination nut consisting of two nut combinations,
When the combination nut is screwed onto the bolt, the two nuts are held together, and when the combination nut is locked, the outer lock nut is simply rotated slightly in the opposite direction.The loosening of the nut can be completely loosened by a simple operation such as simply rotating the outer lock nut slightly in the opposite direction when locking the combination nut. This can be prevented, and the lock can be released by simply rotating the outer lock nut in its original direction, making it possible to use the same combination nut many times.

The material for the combination nut of the present invention is preferably metal or plastic.

Since the present invention is constructed as described above, it is possible to completely prevent the loosening that tends to occur in conventional nuts through simple operation, and eliminates the laborious work such as wrapping hemp when screwing bolts together as in the past. This eliminates the need for the same product at all, and allows the same product to be used multiple times, resulting in cost savings.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway vertical sectional view of the combination nut of the present invention screwed onto a bolt, Fig. 2 is a partially cutaway longitudinal sectional view of the outer lock nut, and Fig. 3 is a partially cutaway longitudinal sectional view of the inner lock nut. 4 is a partially cut away longitudinal sectional view of the combination nut when it is locked; FIG. 5 is a longitudinal sectional view of the main part showing the action of the combination nut when it is locked; and FIG. 6 is another embodiment of the present invention. FIG. 3 is a plan view of the outer lock nut. M...Combination nut, 1...Outer lock nut, 2...Inner lock nut, 1a...First female threaded part, 1b...Second female threaded part, 2a...First male threaded part, 2b...Bottom flange .

Claims (1)

[Claims] 1. It has an outer lock nut and an inner lock nut that is inserted into and cooperates with the outer lock nut, and the outer lock nut is formed by hollowing out the central part of one axial end side of the outer lock nut, and is screwed into the male thread of the bolt. a first female threaded portion, and a second female threaded portion formed by hollowing out the center portion on the other end side in the axial direction and having a larger effective diameter than the first female threaded portion,
The inner lock nut is formed by hollowing out its center portion in the axial direction, and includes a third female threaded portion that is screwed into the male threaded portion of the bolt, a bottom flange formed at one end in the axial direction, and a bottom flange formed at one end in the axial direction. a first male threaded portion formed on the outer circumferential surface of the other end side and screwed into the second female threaded portion of the outer lock nut; and a regulating surface that is formed on the opposite side and comes into contact with the end surface of the second female threaded portion of the outer lock nut to regulate the insertion depth of the inner lock nut into the outer lock nut, and each of the threaded portions is formed in the same direction. and the thread pitch of the first female threaded portion and the male threaded portion of the bolt is set larger than the thread pitch of the second female threaded portion and the first male threaded portion, and the inner lock nut is inserted into the outer lock nut. After they are integrated, they are screwed onto the bolt to fasten the members to be tightened, and then the outer lock nuts are rotated in a direction opposite to the direction of rotation when the members to be tightened are fastened to lock both of the lock nuts onto the bolt. Features a combination lock nut.