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Some examples of DTFLOCK locking applications

1. Application in Automobile Industry

Thread holes on body of the four-drive gear box body used in heavy duty truck manufactured by a leading heavy truck manufacturer were produced with DTFLOCK thread taps. The former fastening included three parts: a class 10 stud, a locking washer and a nut. After the DTFLOCK thread was used, the assembly work has been simplified and loosening of the stud on surface of the gear box body has been eliminated. Up to now, DTFLOCK thread technology has been used in all types of heavy duty trucks manufactured by this corporation.The anti-loosening performance has gradually been acknowledged by automobile industry. Nuts on the car wheel may become loose easily and result in serious potential risk. After DTFLOCK wheel nuts were used, no nut loosening has been reported yet. Presently, transmission shaft and rear axle connection nuts, car engine support nuts, etc also begin to use DTFLOCK nuts.

2. Application in Railway Locomotive

DTFLOCK thread technology was used on bogie designedfor railway cars. The M24 threads at the bogie cross beam end for freight train are DTFLOCK threads. Use of DTFLOCK thread eliminated the freight train dynamic performance deterioration caused by bogie cross beam end thread loosening under extreme conditions and guaranteedsafe and reliable train operation.

3. Application in Diesel Engine

Connection fasteners used in assemblies such as booster, exhaust manifold,etc. of a diesel engine have common requirements high-temperature resistance and intense vibration resistance. Anti-loosening locking nuts such as nylon nuts, chemical adhesives, etc. may fail under high temperature condition. The double nuts + locking washer approach may have better performance under high temperature condition. But the installation is difficult and the anti-loosening performance is not guaranteed.

The unique structure of DTFLOCK nut overcomes the above defects. The tightened fastener can withstand intense vibration at high temperature. When DTFLOCK nuts are used in diesel engine assemblies such as booster, exhaust pipe and oil pipe, the problem of fastener loosening under high temperature is effectively solved. This greatly encourages further DTFLOCK applications in diesel engine industry.

4. Application in Maglev Track Beam

The virgin operation of Shanghai maglev on December 31 of 2002 was a new milestone in human transportation history. The maglev has the highest speed among land traffic, which is up to 500 km/h. During the high speed operation, the elevated track beam will subject to intense vibration with a frequency quickly varying between 0 to 2000 Hz. To prevent the track beam fastener from loosening under vibration with a quickly varying frequency, three fastening schemes were established, among which there is DTFLOCK nuts. After 90 days of trial operation, DTFLOCK anti-loosening nuts demonstrated outstanding anti-loosening performance. No loose DTFLOCK nuts were found on the track beam. The DTFLOCK fastening scheme provided reliable support to the safe operation of the maglev train and further replaced the other two fastening schemes.

5. Application in Construction Machinery

The construction machinery features high power. It will bear large impact load and thus generate intense vibration under working condition. Ordinary bolts and nuts may become loose under impact vibration. To prevent fastener failure, many fastener manufacturers have tried different anti-loosening approaches, such as pre-torqued nuts, swaged nuts, chemical adhesives, etc. These approaches have achieved certain anti-loosening result. But they have two common defects - poor reusability and difficult maintenance. In addition, the chemical adhesives may pollute the environment and cause human injury. After DTFLOCK locking nuts are used, excellent anti-loosening performance and good reusability are achieved and it is easy to maintain. DTFLOCK nuts are now gradually used in more and more key assemblies of construction machinery.

Presently, construction machinery uses DTFLOCK locking nuts in the following assemblies:

  • Concrete mixer truck and crane: support connection, speed reduced support, wheel assembly, etc.
  • Vibrating road roller: coupler, engine universal joint.
  • Excavator: rotary support, track wheel, breaking hammer.
  • Bulldozer: track wheel.
  • Loader: transmission shaft, main transmission differential gear, big bevel gear.

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