Rpc, Inc.

James D Sturgill

William S Appleman

A twistlock operator for a twistlock mechanism has a drive mechanism with a fixed axis and an angularly displaceable twistlock having a pivot axis normally positioned along the fixed axis. A first actuator is drivingly connected to the drive mechanism for thereby permitting rotation of the first actuator and a second actuator is connected to the twistlock. Each of the actuators is generally rectangularly shaped and each has arcuate side bearing surfaces and the bearing surfaces have substantially equal radii of curvature. A tube is pivotally connected to each of the actuators for drivingly connecting the actuators and thereby causing cooperative rotation of the actuators. The tube maintains driving connection between the actuators even when the twistlock pivots and thereby displaces the pivot axis away from the fixed axis.

Twistlock operator

A gantry crane comprising a pair of spaced, parallel rectangular side frames each having top and bottom members and front and rear vertical members connected to the top and bottom members, a front cross beam rigidly connected to each of the side frames at the upper front corners thereof, and a rear cross beam pivotally connected to each of the side frames at the upper rear corners thereof, each of the side frames further including diagonal braces, ground engaging drive wheels mounted on the side frames at the lower corners thereof so that as the gantry crane traverses uneven ground, the wheels maintain ground contact as the rear cross beam pivots with respect to the side frames and the front cross beam absorbs the torsional stress.

Gantry crane

An electro-hydraulic steering system is disclosed for a wide track steerable vehicle which changes the position of each steerable slave wheel to an optimum angle depending on the angle of a hydraulically steerable master wheel. Controls, including electro-hydraulic steering mechanisms, are provided to cause the steerable slave wheels to turn relative to one another to assume and maintain an optimum turning radius and optimum turning relationship as the vehicle operator maneuvers the vehicle along a desired curved path of travel by hydraulically controlling a master steerable wheel. The system minimizes tire wear, reduces structural stresses in the vehicle, and maximizes traction during turning maneuvers. No conventional tie rods are required and the system may be implemented to permit two wheel steering, four wheel crab steering, and four or more wheel coordinated steering. The system uses a position sensor on the hydraulically steerable master wheel to produce a signal to control the positioning of the slave wheels. The signal is digitized to produce a signal which, when compared to a position signal from a position sensor for each slave wheel, causes each slave wheel to assume an optimum position which is about perpendicular to the turning radius of the vehicle.

Hydraulic master-slave steering system for a wide track vehicle

A straddle crane including four vertical column members, two side beam or torsion members, and at least one header beam member, and having wheel or caster assemblies supporting each vertical column member. The straddle crane is implemented for two-wheel or four-wheel steering and for two-wheel or four-wheel driving with open or closed ends. The structures of the header beam and the side beam members are appropriately selected, and the attachment means therefor to the vertical column members are chosen to accommodate the various forces and stresses occurring on the structure during normal operation over uneven terrain or surfaces. The header beam member is sufficiently flexible to permit movement of the casters over and in contact with uneven terrain without producing unacceptable shear stresses in the header beam member. The torsion beam member defines a closed geometric figure in cross section to provide torsional and bending resistance to the loads applied to the vertical columns.

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Roxboro, NC, United States of America

James D Sturgill