Mahlon N Zimmerman

US Patent:

43960936, Aug 2, 1983

Filed:

Jan 19, 1981

Appl. No.:

6/225866

Inventors:

Mahlon N. Zimmerman - Ephrata PA

International Classification:

E06C 506

US Classification:

182208

Abstract:

A ladder or boom extension system includes a base section, at least one movable section in telescoping arrangement with the base section, and a piston rod fixedly connected longitudinally of the base section. A double acting hydraulic cylinder is movable relative to the piston rod in response to the application of hydraulic forces on either side of a fixed piston. A crosshead including cable carrying pulleys is affixed at each end of the hydraulic cylinder whereby the cylinder and the crossheads travel as a unit for extension and retraction while tensioning in response to hydraulic forces. Extension and retraction cables interconnect between the base section and the movable section and are trained about the crosshead pulleys to pull the movable section toward or away from the base section. The crosshead pulleys tension the cables upon longitudinal movement of the cylinder to either extend or retract the movable section or sections relative to the base section as the cylinder is longitudinally urged along the piston rod.

US Patent:

43665918, Jan 4, 1983

Filed:

Nov 12, 1980

Appl. No.:

6/205932

Inventors:

Mahlon N. Zimmerman - Ephrata PA

International Classification:

E01D 100

US Classification:

14 713

Abstract:

The automatic safety gangplank includes a plurality of cooperating ladder sections which are extendable from a fully telescoped or retracted position to an elongated position for extension from a dock to the deck of a ship. The end of the base ladder section is connected to a rotatable turntable and is equipped with a pair of lift cylinders. The turntable and the lift cylinders are connected to respectively rotate and elevate the base segment at all times, when the other gangplank ladder sections are either in their extended or retracted positions. A gangway extends from the end of the outermost ladder section in angular relationship and is positioned upon the deck of the ship. Automatic controls which are responsive to changes in elevation of the deck relative to the dock are provided to automatically either extend, retract, elevate or lower the safety gangplank as may be necessary to continuously maintain a safe walkway between the dock and the deck of the ship for all relative positions of the deck when the ship is either simply docked or when it is being loaded or unloaded.