CN203322014U - Anti-theft and anti-loosening fastener - Google Patents

Abstract

An anti-theft and anti-loosening fastener comprises an outer nut, an inner nut and a bolt, wherein a step hole is formed in the outer nut and is provided with a thread, a thread is arranged at the outer side of the inner nut, the inner nut is connected inside the step hole of the outer nut through the thread at the outer side to form a nesting part, the bolt is connected inside the nesting part through threads, and the lead angle of the threads in the threaded connection position of the outer nut and the inner nut is larger than the lead angle of the threads in the connection position of the outer nut and the bolt. Due to the adoption of the technical scheme, the anti-theft and anti-loosening fastener is simple in structure, low in cost, easy to machine, and wide in application range. Due to the different lead angles, the bolt can not be loosened in the reverse direction after being screwed up, and the purposes of preventing loosening and theft are achieved.

Description

Antitheft locking fastening piece

Technical field

The utility model relates to a kind of fastening piece, refers in particular to a kind of antitheft locking fastening piece.

Background technique

In mechanical engineering and civil engineering, various machine parts, structural member be unable to do without fastening piece in being linked and packed.Fastening piece has brought convenience to mechanical industry and civil engineering, still, as the bolt of fastening piece, an inevitable weakness is arranged, and in strenuous vibration, can get loose voluntarily, causes parts or complete device damage, disintegration, very causes and leads to a disaster; Simultaneously, on some communal facilitys, as the guardrail of expressway, rail, steel construction piece etc. can produce stolen phenomenon often, thus the potential safety hazard of causing.

Antitheft locking device both domestic and external mainly adopts friction locking, mechanical locking and forever locking at present, the locking two kinds of methods that have commonly used rub: the one, adopt compression spring, utilize the rebounding force of compression spring to keep impacting force and the frictional force between screw thread, reach fastening purpose; The 2nd, adopt double nut, utilize nut to make in bolt type to be subject to additional pulling force and additional frictional force to the top effect, reach the effect of locking, but double nut is due to a multiplex nut, and work is very unreliable, has seldom used at present; Machinery is locking commonly used has three kinds: the one, after utilizing slotted nut fastening, pass the aperture of bolt tail and the groove of slotted nut with cotter pin, a kind of is utilize in the groove that the ear built-in connector of lock washer is corresponding or the ear bending of lock washer is adjacent to link, mechanical locking method is reliable, often use the locking method of machinery for important connection, but fastening piece is had specific (special) requirements, cost is high and operates comparatively complexity; Permanent lockingly commonly used permanent lockingly have: spot welding, riveted joint, bonding etc., usually adopt the anaerobic adhesive Bond to be applied to screw thread and screw surface, after fastening nut, Bond can solidify voluntarily this method and the time mostly will destroy threaded fastener in dismounting, can't reuse.

The model utility content

The utility model will solve above-mentioned technical problem, and a kind of antitheft locking fastening piece of simple in structure, low-cost and easy-to processing is provided.

In order to solve the problems of the technologies described above, the technical solution of the utility model is: antitheft locking fastening piece, it is characterized in that: comprise outer nut, inner nut and bolt, in described outer nut, step hole is arranged, described step hole is provided with screw thread, the outside of described inner nut is provided with screw thread, and described inner nut is connected to by outside screw in the step hole of outer nut and forms an embedded member, and described bolt is threaded connection in embedded member.

Further, the screw thread of described outer nut step hole comprises two sections, comprise with the screw thread of inner nut threaded connection place and with the screw thread of bolt joint.

Further, the lift angle of the screw thread of described outer nut and inner nut threaded connection place is greater than the lift angle of the screw thread of outer nut and bolt joint.

Adopt the technical solution of the utility model, simple in structure, low-cost, easily processing, have wide range of applications, and due to the lift angle difference, after bolt screws, just can't oppositely loosen, and reaches the purpose of anti-loose anti-theft.

The accompanying drawing explanation

Below in conjunction with accompanying drawing, embodiment of the present utility model is described in further detail.

Fig. 1 is the utility model structure sectional view;

Fig. 2 is the utility model nut Equivalent Mechanical schematic diagram;

Fig. 3 is the utility model bolt Equivalent Mechanical schematic diagram.

Embodiment

Below in conjunction with the drawings and specific embodiments, the utility model is described further.

Antitheft locking fastening piece shown in Fig. 1, comprise outer nut 1, inner nut 2 and bolt 3, in described outer nut 1, step hole 11 is arranged, described step hole 11 is provided with screw thread, the outside of described inner nut 2 is provided with screw thread, described inner nut 2 is connected to interior composition one embedded member of step hole 11 of outer nut 1 by outside thread, described bolt 3 is threaded connection in embedded member.The screw thread of described step hole 11 comprises two sections, the screw thread of the step hole 11 of described outer nut 1 comprises two sections, comprise with the screw thread of inner nut 2 threaded connection places and with the screw thread of bolt 3 joints, the lift angle of described outer nut 1 and the screw thread of inner nut 2 threaded connection places is greater than the lift angle of outer nut 1 and the screw thread of bolt 3 joints.

If outer nut shown in Fig. 21 is θ with the lift angle of the screw thread of inner nut 2 threaded connection places ₁, the lift angle θ of the screw thread of outer nut 1 and bolt 3 joints ₂, two screw threads are equivalent to the mechanics principle figure on two inclined-planes.

If two inclined-planes all do not have tendency toward sliding, only have pressure, there is no frictional force, i.e. F ₁, F ₂Be 0, so have:

N ₁cosθ ₁＝N ₂cosθ ₂

N ₁sinθ ₁＝F+N ₂sinθ ₂

Have:

$N_1\sin {\mathrm{\θ}}_1=F+N_2\sin {\mathrm{\θ}}_2=F+\frac{N_1\cos {\mathrm{\θ}}_1}{\cos {\mathrm{\θ}}_2}\sin {\mathrm{\θ}}_2=F+N_1\cos {\mathrm{\θ}}_1\tan {\mathrm{\θ}}_2$

N ₁sinθ ₁-N ₁cosθ ₁tanθ ₂＝F

$N_1=\frac{F}{\sin {\mathrm{\θ}}_1-\cos {\mathrm{\θ}}_1\tan {\mathrm{\θ}}_2}$

$N_2=\frac{F}{\sin {\mathrm{\θ}}_1-\cos {\mathrm{\θ}}_1\tan {\mathrm{\θ}}_2}\frac{\cos {\mathrm{\θ}}_1}{\cos {\mathrm{\θ}}_2}$

Due to N ₁, N ₂Be all pressure, must be greater than zero, therefore, above two formulas are set up and are just required sin θ ₁-cos θ ₁Tan θ>=0, i.e. tan θ ₁-tan θ ₂>=0, i.e. θ ₁>=θ ₂

If inclined-plane shown in Fig. 3 does not have, under the frictional force condition, to have:

N ₁cosθ ₁＝N

N ₁sinθ ₁＝F ₀

$\frac{F_0}{N}=\tan {\mathrm{\θ}}_1$

Under the maximum static friction force condition of bottom, bottom can not produce slip, and balance can be set up,

So, require tan θ ₁≤ μ ₀Be that inclination angle of inclined plane is less than the bottom friction angle.

In sum, as long as θ ₁, θ ₂Between meet θ ₁>=θ ₂, tan θ ₁≤ μ ₀, can be good at unidirectional tightened-up between nested nut and bolt, but can not oppositely loosen, reach antitheft locking purpose.

Although specifically show and introduced the utility model in conjunction with preferred embodiment; but the those skilled in the art should be understood that; within not breaking away from the spirit and scope of the present utility model that appended claims limits; in the form and details the utility model is made a variety of changes, be protection domain of the present utility model.

Claims (3)

1. antitheft locking fastening piece, it is characterized in that: comprise outer nut, inner nut and bolt, in described outer nut, step hole is arranged, described step hole is provided with screw thread, the outside of described inner nut is provided with screw thread, described inner nut is connected to by outside screw in the step hole of outer nut and forms an embedded member, and described bolt is threaded connection in embedded member.

2. antitheft locking fastening piece according to claim 1, it is characterized in that: the screw thread of described outer nut step hole comprises two sections, comprise with the screw thread of inner nut threaded connection place and with the screw thread of bolt joint.

3. antitheft locking fastening piece according to claim 1, it is characterized in that: the lift angle of the screw thread of described outer nut and inner nut threaded connection place is greater than the lift angle of the screw thread of outer nut and bolt joint.

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