It is known that the stability of mine workings is achieved by a reasonable choice of the type of support, and by the construction of connecting elements, as a necessary means of ensuring its working capacity.
In the development of modern technical and economic requirements, we have created a new “ЗСГ” lock, which is a clamp-type connecting element, where the compression of the special profile is carried out practically only on the regiments and allows them to realize their compulsory coupling by the principle “friction in a trough”.
Locks of the pliability nodes of the ЗСГ supports of mine workings are intended for interconnection of elements (links) of metal supports made of the profile of СВП-22, СВП-27, СВП-33 according to GOST 18662.

The ЗСГ lock consists of a stabilizer bar (pos.1), clamp (pos.2) and two nuts (pos.3), see Fig. 1.2.
The inclined side walls of the stabilizer bar are designed so that their width gradually increases from the bottom to the top from the concave middle part to the connection with the stops. Due to this, the width of the contact increases, which increases the reliability of blocking the skewing of the plane of the clamp and the shaped bar relative to the longitudinal axis of the cross-section of the connecting links of the support.

Fig. 1 ЗСГ lock assembled;

ЗСГ lock is characterized by a very stable characteristic (deviation of not more than 8-10%) and a higher value of the working resistance (by 1.4-1.8 times) in comparison with the known domestic counterparts.

The stabilizer bar completely covers the inclined side walls of the special profile, provides a tight abutment of the adjacent links of the support and their increased force tightening, counteracts the lateral displacement, which creates smoothness of the work of the pliability node and stability of the working resistance. This design of the stabilizer bar in the form of a single monoblock increases the overall strength of the lock and allows to raise the working resistance to 30% compared to the known domestic counterparts. In comparison with the best foreign analogues (G660), the ЗСГ lock, at equivalence of the working characteristic, has the advantage of reducing the metal consumption by 40%.

Locks of the pliability nodes of the ЗСГ supports of mine workings have 4 designs for the applied mine profiles (see Table 1):

Table 1

Fig. 2 «ЗСГ» lock: a) general view; b) connection node

The ЗСГ lock joints passed bench examinations that showed a high (252-293 kN per node) working resistance and a stable characteristic over the entire range of constructive pliability.

Laboratory tests of samples of the ЗСГ lock joints established that the ones tested on the racks of СВП-22, СВП-27 and СВП-33 (GOST 18662-83) during the check of the pliability node showed the following results:

  1. 1. The maximum working resistance of the pliability node of the arched support of СВП-22 was 335 kN with a pliability of 280 mm, of СВП-27 – 450 kN with a pliability of 280 mm, of СВП-33 – 350 kN with a pliability of 165 mm, which is a sufficiently high value.
  2. 2. The ЗСГ lock is characterized by a very stable characteristic, a high resistance value and can be recommended for advanced use in flexible metal supports of the special profile СВП-22, СВП-27 and СВП-33 (GOST 18662-83) with a maximum bearing ability of at least 700 kN per frame.
  3. 3. The tests have also shown that the resistance value of the pliability node considerably depends on the quality of rolling of the СВП special profile, as well as on the tightening force of the lock nuts with a torque wrench, and therefore the brigades of drifters should be provided with torque wrenches (or nut wrenches).

Fig. 3 and 4 show photos of ЗСГ locks during bench and mine tests:

Fig.4 Mine tests of ЗСГ locks

Fig.3 Bench tests of ЗСГ locks