Basic structure, installation and use of the hotte

2022-08-16
  • Detail

The basic structure and installation of steel wire thread insert

I. The basic structure of steel wire thread insert

steel wire thread insert is a spring-shaped threaded connector made of high-strength, high-precision, diamond shaped stainless steel wire. It is generally used to strengthen the screw holes of aluminum or other low-strength bodies or repair the screw holes damaged due to processing or use

screw the steel wire threaded sleeve into the screw hole of a specific size, and the outer corner of the diamond section closely fits the body, while the inner corner of the diamond section forms a new standard internal thread. A standard screw is screwed into the internal thread formed by this steel wire insert to form a threaded connection with a steel wire insert (see Figure 1)

figure 1

before the steel wire threaded sleeve is screwed into the screw hole, the free state diameter is larger than the diameter of the inner screw used for installing the steel wire threaded sleeve. When screwing in the steel wire threaded sleeve, its diameter needs to be reduced, and after screwing in, it will pop up by itself. Depending on its own elasticity, the steel wire screw sleeve closely fits in the tooth groove of the thread of the machine body, so that it is firmly fixed in the screw hole of the machine body, and it will not loosen when screwing in and out the screws

the outline structure of the steel wire thread sleeve in free state is shown in Figure 2

figure 2

steel wire thread body: it is a spiral body made of diamond section steel wire. Its outer surface forms an external thread, and its inner surface forms an internal thread

mounting handle: it is a straight handle bent inward at one end of the steel wire threaded sleeve. It is specially used to screw the steel wire threaded sleeve into the screw hole. When installing the steel wire screw sleeve, use a special tool to pass through the steel wire screw sleeve body, clamp the installation handle, turn the diameter of the steel wire screw sleeve smaller, and then screw the steel wire screw sleeve into the screw hole

Guide: at the end of the steel wire threaded sleeve with the mounting handle, reduce the diameter of the steel wire threaded sleeve body within the range of 210 with the mounting handle, so that the end can smoothly enter the screw hole when the steel wire threaded sleeve is screwed into the screw hole. This section of steel wire threaded sleeve body is called guide

folded end groove: a groove specially machined for removing the mounting handle. After the steel wire insert is screwed into the screw hole, the mounting handle will lose its function, which will affect the screw to pass through the steel wire insert. In some cases, it is necessary to remove the mounting handle so that the screw is not blocked when it passes through the steel wire insert. For this purpose, a notch is made on the guide section that forms 30 -90 with the mounting handle, so that the mounting handle can be broken from here when impacted by a tool

II. Different types of steel wire threaded sleeves

▲ locking steel wire threaded sleeves

make one or several circles of the steel wire threaded sleeve body into polygonal steel wire threaded sleeves as locking steel wire threaded sleeves

after the locking steel wire insert is screwed into the screw hole, in addition to fixing itself in the screw hole by relying on its own elasticity, it also uses the polygon made to lock the matching screws (see Figure 3)

figure 3

when the screws are screwed into the screw hole of the locking steel wire insert, they are loose before they enter the locking ring of the polygon. When the screws enter the locking ring of the polygon, they need to support the polygon to deform the locking edge, At this time, screw in the screw to overcome the friction given by the locking edge to the screw. After the screw is tightened, this friction force can prevent the screw from loosening itself, thus replacing other locking methods

▲ double wire sleeve structure

double wire sleeve structure is used to repair damaged screw holes with steel wire sleeves

when the screw hole with steel wire insert is damaged, the screw hole of the machine body can be further expanded and double-layer steel wire insert can be installed to repair the damaged screw hole

▲ steel wire insert without mounting handle

steel wire insert without mounting handle is the latest patented product

it is very cumbersome to flush out the mounting handle and take it out after the steel wire insert is screwed into the screw hole, especially for small-size steel wire insert. It seriously affects the installation efficiency of steel wire threaded sleeve

a series of troubles caused by removing the mounting handle are eliminated by using the steel wire threaded sleeve without the mounting handle

the steel wire thread insert without installation handle is to make the buckle of the end into a cone at one end of the steel wire thread insert. The screwing tool is a threaded mandrel, and its end is also made into a corresponding cone shape. The steel wire thread insert can be screwed into the screw hole by the cooperation of the two cones. The process is simple, convenient and reliable. Since the conical part of the steel wire insert can enter the incomplete thread section of the screw hole after being screwed into the screw hole, the conical section of the steel wire insert will not affect the effective thread length of the steel wire insert

the steel wire threaded sleeve without mounting handle is suitable for blind holes

▲ self tapping steel wire insert

self tapping steel wire insert is a new patented product

for low-strength materials such as wood, plastic, cloth bakelite and soft aluminum, it is not necessary to tap out the thread with a tap and then screw in the steel wire threaded sleeve. Using self tapping steel wire thread insert can squeeze the matrix thread with its own external thread in the light hole like self tapping screw. At the same time, it is embedded in the thread to form a new standard thread hole

the screw in of self tapping steel wire thread insert mainly depends on the threaded installation mandrel. In the process of screwing in, the mandrel thread matches with the steel wire insert and supports the steel wire insert so that its external thread can be squeezed into the base material. When the threaded mandrel exits, the steel wire insert is fixed in the threaded hole extruded by itself by its own elasticity, and the thread size of the mandrel determines the size of the steel wire insert screw hole

the front end of the self tapping steel wire insert has a taper, and the mandrel thread also has the same taper, so as to play a guiding role in the extrusion process

III. installation and use of steel wire insert

1. Basic requirements for the screw holes formed after the installation of ordinary steel wire insert

steel wire insert is used to increase the strength of the matrix screw holes or repair the damaged screw holes. After the steel wire thread insert is screwed into a specific internal thread, the basic tooth pattern of the new screw hole formed shall comply with the provisions of GB basic tooth pattern of ordinary thread. The dimensions of each part of the thread shall comply with the provisions of GB basic dimensions of ordinary threads, and the accuracy of the thread can be 5h as required 6h or 7h

the depth of the screw hole of the steel wire thread sleeve shall be selected as required

after the steel wire threaded sleeve is screwed into the screw hole, the upper end should be lower than the end face of the screw hole by 0 5 pitches

after the steel wire threaded sleeve is screwed into the screw hole, it shall be closely attached to the screw hole wall along the tooth groove of the screw hole, and there shall be no jumping teeth or separation from the hole wall

after the steel wire threaded sleeve is screwed into the screw hole, the screw plug gauge with corresponding accuracy can be used to check whether its accuracy meets the requirements or trial assembly with screws

the through end or screw of the thread plug gauge should be able to smoothly pass through the full length of the steel wire threaded sleeve

it is not allowed to use a tap to calibrate the screw hole equipped with a steel wire screw sleeve (i.e. it is not allowed to return the thread)

if the steel wire insert is screwed in improperly, it can be pulled out with an exit tool, and a new steel wire insert can be screwed in again. The withdrawn steel wire threaded sleeve is generally no longer used

2. Preparation of threaded hole for installing steel wire screw sleeve

① smooth hole processing before tapping

▲ hole diameter

the diameter of bottom hole before tapping should make the inner diameter of thread after tapping meet the provisions of the inner diameter of thread for installing steel wire screw sleeve (HB or gjb119.)

when selecting the drill bit diameter, the possible production differences in drilling and tapping of different materials should be considered

if there is no standard data to improve its performance by physical and chemical methods such as blending, copolymerization or surface modification, it can also refer to the following public test calculation to select the drill bit diameter

d drill bit =d+ (0..3) p

d - nominal diameter of thread

p - pitch

▲ hole depth

because the steel wire insert can only be installed to the fully threaded part and it needs to be lower than the end face L1 (see Figure 4), Therefore, the drilling depth l of the blind hole should be:

Figure 4

l=l0 + L1 + L2

l0 - the length of the steel wire insert after it is screwed into the screw hole

l1= (0..5) P

L2 = 5p

L = l0 + 6p

for the through hole drilling depth l should be:

according to the number of free-form turns of the steel wire insert, the assembly can be found out from the corresponding standards.The length of the state l0

▲ chamfer

the chamfer of the screw hole for installing the steel wire screw sleeve should be 120 pairs. The exports of developed countries are mainly at the middle and low ends, and the diameter is up to the outer diameter of the thread. The chamfer is not easy to be too large. Don't fall 90

② tapping and the strain continues to increase) the control situation introduced by the national standard is constant strain control

different types of taps are selected according to the body material and screw hole precision processing method to ensure the accuracy requirements and improve the tap life

after tapping, use the corresponding thread plug gauge to check whether the screw hole meets the specified accuracy requirements. Especially when a new tap is used and the tap is close to wear, the screw hole must be checked with a thread plug gauge to identify whether the tap is available

the tapping depth should be such that the length of the complete thread is not less than the length of the steel wire insert in the assembled state

3. Installation of steel wire screw sleeve

steel wire screw sleeve is to use a special tool to clamp its installation handle, rotate the installation handle to reduce its diameter and screw it into the screw hole along the thread line of the screw hole

3.1 screw in tool of ordinary steel wire insert and its use

a sleeve type

typical structure of sleeve type screw in tool (Fig. 5)

it is composed of guide sleeve, sleeve, mandrel and handle. The guide sleeve is a copper sleeve with conical internal thread, which plays the role of shrinking and guiding the steel wire insert. There is a notch at the front end of the mandrel to clamp the installation handle of the steel wire insert, The thread on the back section of the mandrel is matched with the sleeve thread to prevent the mandrel from jumping when being pushed forward when screwing into the steel wire threaded sleeve

Figure 5

steps for installing the steel wire insert using the sleeve type screw in tool:

I) put the steel wire insert to be screwed in from the notch of the sleeve into the sleeve, so that the installation handle of the steel wire insert faces forward

II) push the mandrel forward, insert the steel wire insert and make the notch of the mandrel catch the mounting handle of the steel wire insert

Ⅲ) rotate the handle to make the mandrel thread and sleeve thread bite and continue to move forward until the end of the steel wire threaded sleeve protrudes from the end face of the guide sleeve by a buckle

Ⅳ) align the end of the steel wire insert with the base screw hole, hold the sleeve with one hand and straighten it, and continue to rotate the mandrel with the other hand until the steel wire insert comes out of the guide sleeve, lift the sleeve upward, and observe whether the steel wire insert is in place. If it is not in place, continue to rotate the mandrel until it is in place

the structure of sleeve type screw in tools is also different, some of which have no threaded limit at the rear section of the mandrel, and some have threads at the front end

b guide sleeve and mandrel separate screw in tool

separate the guide sleeve and mandrel, which is convenient and flexible to use. (as shown in Figure 6)

C simple screw in tool

simple screw in tool is to open a slot at the end of a straight rod and install a lever at the other end. The diameter of the slotted end should be slightly smaller than the inner diameter of the standard thread formed by the screw in of the steel wire insert, as shown in Figure 7

Figure 6 figure 7

simple workers can also be used in the field of sportswear and protective clothing. It is convenient to use, high efficiency and low cost, but the assembly will be smooth only if the operating workers are skilled and the guide and processing of steel wire thread sleeves are good. Generally, it is suitable for coarse thread. The tool with guide sleeve is more reliable for large diameter fine thread

3.2 screwing in of locking steel wire threaded sleeve

locking steel wire threaded sleeve, because the locking edge of the polygon reduces the inner diameter of the locking ring after the threaded sleeve is screwed into the screw hole, the diameter of the screw in tool rod should also be reduced to prevent the rod from being stuck

generally, the screw in tool with guide sleeve and thread at the front end of mandrel is best used for the screw in of locking steel wire insert, so as to prevent tooth jumping in the locking ring (see Figure 8)

figure 8

3.3 remove the handle

when it is necessary to remove the installation handle of the steel wire threaded sleeve according to the structural requirements, the steel wire threaded sleeve with a broken groove shall be selected. Generally, the processing depth of through-hole and screw hole is limited, and the screw may exceed

Copyright © 2011 JIN SHI