Gangway having self-raising assembly
A raising assembly for use with a gangway connected for rotation between a raised stowed position and a lowered deployed position. The raising assembly comprises at least one fluid actuated cylinder connected to the gangway. A raising actuator is operative to cause operation of the cylinder in a manner that rotates the gangway toward the stowed position while the raising actuator is continuously activated by an operator. A lowering actuator is operative to cause operation of the cylinder in a manner that rotates the gangway toward the deployed position due to gravitational forces while the lowering actuator is continuously activated by the operator. The raising assembly is configured to maintain the gangway at a current position between the stowed position and the deployed position if the operator does one of ceasing to activate the raising actuator while raising the gangway or ceasing to activate the lowering actuator while lowering the gangway.
1. A raising assembly for use with a gangway connected for rotation between a raised stowed position and a lowered deployed position, said raising assembly comprising:
at least one fluid actuated cylinder connected to the gangway;
a raising actuator operative to cause operation of the cylinder in a manner that rotates the gangway toward the stowed position while the raising actuator is continuously activated by an operator; and
a lowering actuator operative to cause operation of the cylinder in a manner that rotates the gangway toward the deployed position due to gravitational forces while the lowering actuator is continuously activated by the operator;
wherein the raising assembly is configured to maintain the gangway at a current position between the stowed position and the deployed position if the operator does one of ceasing to activate the raising actuator while raising the gangway or ceasing to activate the lowering actuator while lowering the gangway.
2. A raising assembly as set forth in claim 1 , wherein the raising actuator includes a rope and the raising actuator is activated by the operator pulling the rope.
3. A raising assembly as set forth in claim 2 , wherein the lowering actuator activates at least one pilot operated valve to allow flow therethrough in a first flow direction while a foot pedal is being depressed by the operator.
4. A raising assembly as set forth in claim 3 , wherein fluid flowing through the at least one pilot operated valve in the first flow direction travels from a first side of a piston in the fluid actuated cylinder to a second side of the piston.
5. A raising assembly as set forth in claim 4 , wherein the first side of the fluid actuated cylinder is a rod side and the second side of the fluid actuated cylinder is a blind side.
6. A raising assembly as set forth in claim 5 , further comprising a reservoir configured to contain excess fluid due to a difference in volume between the rod side and blind side of the fluid actuated cylinder.
7. A raising assembly as set forth in claim 3 , wherein the fluid actuated cylinder retracts to rotate the gangway toward the stowed position.
8. A raising assembly as set forth in claim 1 , wherein the at least one fluid actuated cylinder includes first and second cylinders situated on left and right sides of the gangway, respectively.
9. A raising assembly as set forth in claim 1 , wherein each of said raising actuator and said lowering actuator comprises a spring-loaded plunger.
10. A raising assembly as set forth in claim 1 , comprising a hydraulic pump driven by a motor.