JPH01176808A - Locking nut and bolt - Google Patents

Abstract

PURPOSE:To make a locking function of a nut perfect by forming concentric grooves in a ring-like form on a central part of a circumference of a bearing surface, setting the bearing surface thereinside lower than that of thereoutside to prevent the same from being in contact to an article to be fastened, and unifying the bearing surface pressures. CONSTITUTION:When a nut 2 is pressurized by a body 7 fastened thereby with a proper force, pressure is applied on a bearing surface 3 alone. Reaction of the bearing surface 3 works obliquely upward, turns in the upper part of the nut 2, and reaches a lower screw part. Compression deformation is generated on an outer periphery of the nut 2, while extension deformation on an inner periphery thereof. A bearing surface 4 contacts the fastened body only when excessive pressure such as oscillations or shock is applied on the bearing surface 3 to prevent a permanent deformation remaining of the nut. The inner side of the screw is deformed independently on a screw body, so that it adsorbs the strain against a shaft when screwing with a bolt 1. A screw cutout 6 on the upper side of the nut 2 improves in the function of hanging the bolt, and improves an elastic pressure of the nut. The locking effect of the nut can be obtained with a simple construction.

Description

[Detailed Description of the Invention] The biggest drawback of screws is that they loosen after they are installed, and various methods have been devised since ancient times to prevent this, but each of them has its advantages and disadvantages, and is not completely perfect. The current situation is that there is nothing.

By the way, loosening of screws includes (1) Non-rotating loosening Loosening that does not occur due to the return rotation of the nut, which is caused by the settling of irregularities such as on the bicep surface. (2) Loosening due to rotation: Loosening due to rotation of the nut due to external force such as vibration.

In the case of (1), the progress can be prevented by stopping at a certain point or by re-tightening, but in the case of (2), this is difficult to prevent and requires other parts or adhesives. Many people have used methods that take time and effort, but there is still no perfect solution. − Therefore, we have considered countermeasures against the problem, assuming that screws naturally loosen, but we have taken the opposite approach and believe that one of the major causes of loosening is the pressure on the seat surface. It is necessary to pay attention to the uniformity of

Any vibrations applied to the nut will eventually result in horizontal sliding motion of the seat surface, but if the pressure distribution on the seat surface is not uniform at this time, frictional resistance will be concentrated in the area of maximum pressure. It is. However, the nut has a donut-shaped seat surface because the bolt needs to pass through the center, so if one part is strongly pressurized, the pressure on that target side will be less, and the left and right sides will be affected. It is natural that it will be uneven. Therefore, since the vibration moves the seat horizontally, the vibration moves the seat to the left and right. However, since nuts rotate in the tightening direction (+) and loosening direction (-), there is a large resistance to movement in the (+) direction and a small resistance to movement in the (-) direction. The vibrations tend to rotate the nut in the direction of loosening it.

Normally, when a screw is tightened, the male and female threads are crimped together, and the frictional force generated between them resists the force in the direction of loosening the screw, so if a properly made screw is used correctly,
It's not something that will come loose.

However, (a) the tightening surface is sagging, caved in, and (b) galling. (c) Gaps between clamped plates due to waving, warping, beams, etc. of the plates.

(d) Dripping of paint during painting, uneven peeling of the paint film.

(e) Immediate entry of objects into gaps.

etc., the stress of the tightening torque applied to the bearing surface will be applied unevenly to the threaded surface of the bolt and the bearing surface of the nut, so the average left and right frictional resistance of the bearing surface, that is, the stress of the tightening torque applied to the bearing surface will be This causes an imbalance in the force exerted by the nut, causing the nut to loosen and rotate.

In addition, although the seat surface of the nut should originally be perpendicular to the axis, it may have a slight inclination depending on the machining precision, and in addition to the above-mentioned problems with the tightening conditions, there is a risk of loosening. This is a major cause.

By the way, elastic washers are generally used to prevent screws from loosening, but this is used to prevent shock from being transmitted to the screws, and it does not have the power to correct the average pressure on the left and right sides, and also prevents bubbling. Nuts cannot be expected to do anything more than prevent loosening and rotation by expanding the seat surface outward.

The present invention is a new proposal for equalizing the seat pressure, which is a major cause of such nut loosening, and thereby attempts to perfect the locking function of the nut.

To explain this with reference to the drawings, Figure 1 schematically represents the principle of the present invention, in which a groove (5) is concentrically carved in the center of the circumference of the seat surface of the nut (2). The seat surface (4) on the inner circumference of this groove (5) is slightly lower than the seat surface (3) on the outer circumference so that it does not come into contact with the object to be tightened (7) during tightening. Furthermore, a screw notch (6) is provided on the upper side of the nut (2) to prevent it from getting caught on the bolt (1).

Since the present invention has such a structure, when the nut (2) is properly tightened and pressurized against the tightened body (7), the seat surface (3)
Pressure is applied to the nut (2), and the reaction force from the seat rises diagonally upward, reverses itself at the top of the nut (2), and reaches the threaded portion at the bottom of the nut (2). At this time, the outer edge of the nut (2) will experience compressive strain, and the inner edge will experience stretching strain. The seat surface (4) on the inner circumference of the seat contacts the tightened body (7) only when excessive pressure is applied to the seat surface (3) due to vibration or impact, causing permanent strain on the nut (2). It works so as not to leave any residue. Like this, this nut (
2) Compared to conventional screws, the inherent elasticity of the screw acts on the reciprocation of compression and elongation, so it has doubled, and on top of that, the inside of the screw can strain independently of the screw body, so It is possible to absorb the strain on the shaft when screwed with the bolt (1), and to make the angle appropriate, thereby correcting the left-right balance of the force applied to the seat surface and the threaded part. The screw notch (6) on the upper side of the nut (2) can enhance the function of hanging the bolt, thereby increasing the elasticity of the nut. The nut shown in Figure 2 was designed to further strengthen the above effect; this nut has one more ring-shaped groove (8) carved on the outer periphery, and the central seat surface (11) is on the outer periphery. Lower than the seat surface (3), the inner circumferential seat surface (4
) is made lower than the seat surface (11). This should be made of a highly elastic material such as steel, and its performance is great.

Figure 3 shows a nut with a groove (9) on the top surface similar to the bottom surface, and Figure 4 shows a ring-shaped groove (1) around the outside of the top of the nut.
0) is provided. In this way, the effect of the present invention can be enhanced because strain can be easily created at the locations indicated by the horizontal dotted lines in the drawings.

Figure 5 shows a compressive strain section (12) created from the outside on the upper side of Figure 4 to add the effect of a prevailing torque nut, which strengthens the effect of this invention. .

Since the present invention has such a very simple structure, it is a strong lock nut that can be manufactured at low cost regardless of size, can be used repeatedly without causing mistakes, and can be used many times without damaging the threads. Regardless of the target, it is possible to apply a uniform load to the seat surface and each screw thread even if the object to be tightened has some difficulty such as unevenness or slope, and its simplicity makes it suitable for tightening with automatic assembly machines. Because of its unique elasticity, it can withstand relative movement between parts, stickiness, vibration, and warming of the screw due to thermal changes without losing its anti-rotation effect without using additional parts such as spring washers or double nuts.

Furthermore, this invention can be applied not only to nuts, but also to bolts and small screws, and by simply applying this idea to the heads of bolts and screws, it is possible to create products with a great anti-rotation effect.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention. Figure 1 is a sectional view showing the principle of the invention, and Figures 2, 3, 4, and 5 are sectional views showing applied examples of the invention. It is. 1: Bolt 2: Nut 3: Outer seat surface 4: Inner seat surface 5: Groove 6
: Screw notch 7: Tightened object 8: Groove on outer periphery 9: Groove on top surface 10: Groove on outer periphery Il: Seat surface in center 12: Compressive strain part drawing

Claims (1)

[Claims] A ring-shaped concentric groove is carved in the center of the circumference of the seat,
A locking nut and bolt characterized in that the inner seat surface is lower than the outer seat surface so that it does not touch the object to be tightened.