Snubber for shovel dipper

A dipper assembly for a mining shovel, the dipper assembly comprising:

• a body defining a material receiving opening and a material discharging opening;
• a door pivotably coupled to the body to selectively close the material discharging opening;
• and
• a snubber for dampening movement of the door relative to the body, the snubber including,
• a housing coupled to one of the body and the door, the housing defining an enclosed chamber,
• a shaft including a first end and a second end, the shaft supported for rotation relative to the housing about a shaft axis, rotation of the shaft dampened by fluid in the enclosed chamber,
• a shaft cavity positioned between an outer surface of a portion of the shaft and the housing,
• a high pressure fluid seal engaging an outer surface of the shaft at a position between the first end of the shaft and the second end of the shaft, the fluid seal including a low pressure side and a high pressure side adjacent the shaft cavity, and
• an arm including a first end and a second end, the first end of the arm coupled to the first end of the shaft, the second end of the arm pivotably coupled to the other of the body and the door, movement of the door relative to the body driving the arm to pivot and rotate the shaft about the shaft axis.

A damper for dampening rotation of a dipper door relative to a dipper body of a mining shovel, the damper comprising:

• a housing defining an enclosed chamber;
• a shaft including a first end and a second end, the shaft supported for rotation relative to the housing about a shaft axis, rotation of the shaft dampened by fluid in the enclosed chamber;
• a shaft cavity positioned between an outer surface of a portion of the shaft and the housing;
• an arm including a first end and a second end, the first end of the arm coupled to the first end of the shaft, the second end of the arm configured to be coupled to one of the dipper door and the dipper body such that rotation of the dipper door drives the arm to rotate the shaft;
• and
• a seal member positioned between a side surface of the housing and the first end of the arm, the seal member supporting a dust seal, a high pressure fluid seal, and a vacuum seal, the dust seal preventing ingress of contaminants into the shaft cavity, the high pressure fluid seal engaging an outer surface of the shaft and preventing fluid flow from the shaft cavity along an outer surface of the shaft, the high pressure fluid seal positioned between the dust seal and the shaft cavity, the vacuum seal positioned between the dust seal and the high pressure fluid seal.