Patent ID: 8181758

Claim:
A damping device comprising: a cylinder having a first end and a second end opposite to the first end, an interior space defined within the cylinder, the first end having a first hole interconnecting with the interior space, the second end having a second hole interconnecting with the interior space, damping medium filled within the interior space; a resilient member located in the interior space and having a first end and a second end opposite to the first end, the first end of the resilient member contacting against an inside of the first end of the cylinder; a seal member sealing the first hole in the first end of the cylinder; a piston movably received in the interior space and urged by the second end of the resilient member, the piston including a piston body, a connection portion and a neck portion connected between the piston body and the connection portion, the second end of the resilient member connected to the connection portion, the piston body having a recess and at least one opening penetrating through the piston body, the connection portion having at least one notch corresponding in position to the opening, a gap defined between the piston and an inner periphery of the interior space, said connection portion including a first plate and a second plate which is perpendicularly connected to said first plate, said second end of the resilient member being connected to said first plate and said second plate; a control valve movably connected to the neck portion of the piston and having a contact surface which faces the opening of the piston body; a piston rod located in the interior space and having a first end and a second end opposite to the first end, the first end of the piston rod engaged with the recess of the piston body and the second end of the piston rod extending out from the second end of the cylinder; a cover assembly sealing the second hole in the second end of the cylinder and including a hollow mounting member which is fixed to the cylinder, a first resilient ring received in the mounting member and connected with the piston rod, and a second resilient ring fitted on an outside of the mounting member and in contact with the inner periphery of the interior space, and a damping member located between the piston and the cover assembly.