Method of Differential Thread Connection with a Stopper.

A presentation given by the Russian developer.

“Finding ways to increase reliability of the thread connections was the main goal of the research done by our company while developing a new method of connecting/fastening parts and structural components. We aimed at finding a solution using the standard elements of the thread connections avoiding complex technical combinations that would be difficult to introduce to the mass production and to use in the fields of application. As a result, we have come up with a new type of multi-purpose thread connection that can be used to fasten bolts and nuts (without tack welding), to connect pipes of any diameter and cylinders as well as rails, metal sheets (cladding) e.t.c.

The achieved technical properties are distinguished by the increased stiffness of the connection due to the increased tightening force of the connected parts. The fastening can be done with a tremendous force and at the same time with a limited torque. The axial tightening force can be increased up to 8 – 12 times compared to the regular thread connection. For example, in order to tighten the M8 bolt with the force of 915 kgf it is necessary to apply the torque of 110 kgf under the normal circumstances. Our technology enables us to apply the torque of only 22,5 kgf.cm (or five times less) to achieve the tightening force of 915 kgf.

Our technology has a vital element with a differential thread. Using the connection with a differential thread is similar to the regular connection with a small step thread. Yet the stiffness is not smaller than that rendered by the existing methods. For example, in the connection of two shafts (large diameter pipes) the main step of the thread is S1=3 mm, but the difference of the steps of the differential range is ΔS=S2-S1; ΔS =0,25 mm. Thus the stiffness properties of the thread will be the same as the properties of the S1=3 mm thread, and the tightening force will be the same as for the step of ΔS =0,25 mm with a smaller lifting angle or , by increasing the torque while tightening we can significantly increase the stiffness of the whole connection. Which option to use depends on the purpose of the connection of the shafts (pipes). Most importantly that the design engineers and the end-users get a lot of tuning capabilities to accomplish the optimal result depending on the situation.

In some variations of the design we use a stopping element. Depending on the design, the thread connection can have a “stopper effect”. It is also possible to make a connection so it cannot be disassembled as a pin or a welding seam. Here we offer a wide range of tuning options depending on the problems that have to be solved.

The connected parts may be made with internal or external threads. The contacting surfaces of the connected parts may have different shapes: flat, conical, spherical e.t.c. The most important is the order of assembly that also provides certain benefits.

Our method can be used in such extreme conditions as:

  • torque transfer mechanisms
  • high pressure pipelines
  • mechanisms working in the conditions of high vibrations
  • high strength structures

We have developed a range of solutions for various industries such as connection of railroad rails and connecting the pipes for the oil and gas production. It is likely that our technology will offer advantages in the offshore oil and gas exploration.

Here are the main benefits of our thread connection technology:

• high axial tightening force with low torque
• retaining of the tightening force regardless of any external impacts
• “ the stopper effect”
• manufacturing simplicity – no special thread is required
• possibility to use the standard types of the threads
• possibility to use on the automated assembly lines
• possibility to use the connection (and connected elements) many times

The economic effect of the implementation of our technology can be very significant if correctly introduced to the market in comparison with all the existing methods.

In order to define the fields of application and tuning options we would like to meet with the interested partners and provide all the information on the technology as well as show the samples.”