Gangway having self-raising assembly

1. A gangway comprising:

a fixed platform;

a support structure connected to the fixed platform in a manner that allows the support structure to rotate with respect to the fixed platform between a raised stowed position and a lowered deployed position; and

a raising assembly operative to rotate the support structure from the deployed position to the stowed position, said raising assembly including:

at least one fluid actuated cylinder connected to the support structure;

a raising actuator operative to cause operation of the cylinder in a manner that rotates the support structure toward the stowed position, said raising actuator being connected to a rope that is pulled by an operator to raise the support structure; and

a lowering actuator operative to cause operation of the cylinder in a manner that rotates the support structure toward the deployed position, said lowering actuator being connected to a foot pedal that is depressed by an operator to lower the support structure.

2. A gangway as set forth in claim 1 , wherein the raising assembly is configured to maintain the support structure at a current position between the stowed position and the deployed position if the operator does one of releasing the rope while raising the support structure or ceases to depress the foot pedal while lowering the support structure.

3. A gangway 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 the foot pedal is being depressed by the operator.

4. A gangway 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 gangway 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 gangway 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 gangway as set forth in claim 3 , wherein the fluid actuated cylinder retracts to rotate the support structure toward the stowed position.

8. A gangway 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 support structure, respectively.

9. A gangway as set forth in claim 1 , wherein each of said raising actuator and said lowering actuator comprises a spring-loaded plunger.

10. A gangway as set forth in claim 1 , wherein the raising assembly includes a hydraulic pump driven by a motor.

11. A gangway as set forth in claim 1 , wherein said platform structure comprises a base tread structure adapted to be attached to fixed structure, said base tread structure having a housing containing the raising actuator, the lowering actuator, and a motor.

12. A gangway comprising:

a fixed platform;

a support structure connected to the fixed platform in a manner that allows the support structure to rotate with respect to the fixed platform between a raised stowed position and a lowered deployed position; and

a raising assembly operative to rotate the support structure from the deployed position to the stowed position, said raising assembly including:

at least one fluid actuated cylinder connected to the support structure;

a raising actuator operative to cause operation of the cylinder in a manner that rotates the support structure 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 support structure toward the deployed position while the lowering actuator is continuously activated by the operator,

wherein the raising assembly is configured to maintain the support structure 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 support structure or ceasing to activate the lowering actuator while lowering the support structure.

13. A gangway as set forth in claim 12 , wherein the lowering actuator activates at least one pilot operated valve to allow flow therethrough in a first flow direction while the lowering actuator is being activated by the operator.

14. A gangway as set forth in claim 13 , wherein fluid flowing through the at least one pilot operated valve in the first flow direction travels from a rod side of the fluid actuated cylinder to a blind side of the cylinder.

15. A gangway as set forth in claim 14 , further comprising a reservoir configured to contain excess fluid, the reservoir being mounted in a housing below the platform structure.

16. A gangway as set forth in claim 15 , wherein the at least one fluid actuated cylinder includes first and second cylinders situated on left and right sides of the support structure, respectively.

17. A gangway as set forth in claim 12 , wherein at least one of said raising actuator and said lowering actuator comprises a spring-loaded plunger.

18. A gangway as set forth in claim 12 , wherein the raising assembly includes a hydraulic pump driven by one of a pneumatic motor and an electric motor.

19. A gangway comprising:

a base tread structure adapted to be attached to fixed structure, said base tread structure including a housing;

a support structure connected to the base tread structure in a manner that allows the support structure to rotate with respect to the base tread structure between a raised stowed position and a lowered deployed position; and

a raising assembly operative to rotate the support structure from the deployed position to the stowed position, said raising assembly including:

at least one fluid actuated cylinder connected between the base tread structure and a distal end of the support structure; and

fluid handling components operative to supply fluid to and from said fluid actuated cylinder, said fluid handling components including at least one actuator operative to cause operation of the fluid actuated cylinder in a manner that rotates the support structure between the stowed position and the deployed position, a hydraulic pump, and a motor for driving the hydraulic pump,

wherein the at least one actuator, the hydraulic pump, and the motor are contained in the housing.

20. A gangway as set forth in claim 19 , wherein the least one actuator comprises a raising actuator and a lowering actuator.

21. A gangway as set forth in claim 20 , wherein each of said raising actuator and said lowering actuator comprises a spring-loaded plunger.

22. A gangway as set forth in claim 19 , wherein said fluid handling components further comprise a reservoir for containing a quantity of said fluid, the reservoir being located in the housing.

23. A raising assembly for use with a gangway having a support structure connected to a fixed platform in a manner that allows the support structure to rotate with respect to the fixed platform between a raised stowed position and a lowered deployed position, said raising assembly comprising:

at least one fluid actuated cylinder for connection to the support structure;

a raising actuator operative to cause operation of the cylinder in a manner that rotates the support structure toward the stowed position while the raising actuator is continuously activated by an operator;

a lowering actuator operative to cause operation of the cylinder in a manner that rotates the support structure toward the deployed position while the lowering actuator is continuously activated by the operator;

a hydraulic pump; and

a motor for driving the hydraulic pump;

wherein the raising assembly is configured to maintain the support structure 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 support structure or ceasing to activate the lowering actuator while lowering the support structure.