Articulated mine door opening mechanism

A mine door system comprising:

• a mine door comprising a door leaf adapted to be hinged at one side to a door frame defining an entry, the door leaf comprising a panel, a draw bar extending from the panel and adapted to move from a retracted position to an extended position relative to the panel, and a biasing member arranged to bias the draw bar toward the retracted position;
• and
• an articulated door-moving mechanism that articulates between a first configuration in which the mechanism applies a first door-moving force to the door leaf and moves the door leaf at a first speed and a second configuration in which the mechanism applies a second door-moving force to the door leaf that is greater than the first door-moving force and moves the door leaf at a second speed less than the first speed, wherein the articulated door moving mechanism comprises:
• a motor for driving pivoting movement of the door leaf;
• a variable length crank drivingly connected to the motor so the motor can drive rotation of the variable length crank, the variable length crank comprising first and second crank arms connected to one another for pivoting movement relative to one another to change the length of the crank between a first length and a second length that is shorter than the first length, and a crank arm biasing member arranged to bias the first and second crank arms toward a configuration in which the variable length crank has the first length and to allow movement of the first and second crank arms against the bias to a configuration in which the variable length crank has the second length;
• and
• an elongate link, the variable length crank being connected to the elongate link at one end of the crank and the draw bar of the door leaf being connected to the elongate link at an opposite end of the elongate link,
• wherein the system is designed so damping of the draw bar biasing member and damping of the crank arm biasing member substantially prevent any resonant dynamic interactions between the drawbar biasing member and the crank arm biasing member.

A mine door system comprising:

• a mine door comprising a door leaf adapted to be hinged at one side to a door frame defining an entry, the door leaf comprising a panel, a draw bar extending from the panel and adapted to move from a retracted position to an extended position relative to the panel, and a biasing member arranged to bias the draw bar toward the retracted position;
• and
• an articulated door-moving mechanism that articulates between a first configuration in which the mechanism applies a first door-moving force to the door leaf and moves the door leaf at a first speed and a second configuration in which the mechanism applies a second door-moving force to the door leaf that is greater than the first door-moving force and moves the door leaf at a second speed less than the first speed, wherein the articulated door moving mechanism comprises:
• a motor for driving pivoting movement of said door leaf;
• a variable length crank drivingly connected to the motor so the motor can drive rotation of the variable length crank, the variable length crank comprising first and second crank arms connected to one another for pivoting movement relative to one another to change the length of the crank between a first length and a second length that is shorter than the first length, and a crank arm biasing member arranged to bias the first and second crank arms toward a configuration in which the variable length crank has the first length and to allow movement of the first and second crank arms against the bias to a configuration in which the variable length crank has the second length;
• and
• an elongate link, the variable length crank being connected to the elongate link at one end of the elongate link, and the draw bar of the door leaf being connected to the elongate link at an opposite end of the elongate link,
• wherein at least one of the draw bar biasing member and the crank arm biasing member comprises a series of washers arranged to form a Bellville spring.

A mine door system comprising:

• a mine door comprising a door leaf adapted to be hinged at one side to a door frame defining an entry;
• and
• an articulated door-moving mechanism that articulates between a first configuration in which the mechanism applies a first door-moving force to the door leaf and moves the door leaf at a first speed and a second configuration in which the mechanism applies a second door-moving force to the door leaf that is greater than the first door-moving force and moves the door leaf at a second speed less than the first speed, wherein the articulated door moving mechanism comprises:
• a motor for driving pivoting movement of the door leaf;
• a variable length crank drivingly connected to the motor so the motor can drive rotation of the variable length crank, the variable length crank having a first length when the articulated door-moving mechanism is in the first configuration and a second length different from said first length when the articulated door-moving mechanism is in the second configuration;
• a link connecting the variable length crank to the door leaf;
• wherein the door leaf comprises a panel and a draw bar extending from the panel, the link being connected to the draw bar adjacent an end of the draw bar opposite the panel;
• wherein the door leaf is adapted to allow the draw bar to move relative to the panel from a retracted position to an extended position, the door leaf further comprising a draw bar biasing member arranged to bias the draw bar toward the retracted position.