b the tongue 21 will be pushed and the shaft 20 will slide inwards in the hollow tube 10 the sliding member 23 remains stationary due to its rigidity when the shaft 20 is just moved inwards the coupling ring 25 is pushed by the shaft 20 and the front side is stopped by the sliding member 23 thus the coupling ring 25 is compressed and deformed to slightly expand its outer diameter referring to fig5 a and an interference occurs in the interior of the hollow tube 10 to generate a required buffer resistant force in this embodiment both the resilient member 221 and the coupling ring 25 provide buffer forces the shaft 20 has a neck section 222 to couple with an adjustment member 26 to adjust the sliding distance of the sliding member 23 as shown in fig6 so that the deformation of the coupling ring 25 may be altered to adjust the buffer force refer to fig7 for a fourth embodiment of the invention the resilient member 221 is dispensed with the buffer force is provided by the coupling ring 25 only of course an adjustment mechanism may also be provided on the other hand also see fig2 the gaps g 1 and g 2 on two sides may also be altered to adjust the buffer force generated in applications besides being fastened directly to the cabinet wall 72 the invention may also be mounted on a bracket 42 not shown in fig7 referring to fig8 a bracket 42 is mounted on a hinge seat 73 which has an annular member 41 on one side the annular ring.