Horizontal reference marker

• US 6,535,834 B1
• Filed: 07/10/2001
• Issued: 03/18/2003
• Est. Priority Date: 09/30/1998
• Status: Expired due to Term

• Current Assignee: ABB AB (ABB Limited)
• Original Assignee: ABB AB (ABB Limited)
• Inventors: Bryfors, Uno, Johansson, Christer
• Primary Examiner(s): Hoff, Marc S.
• Assistant Examiner(s): Raymond, Edward
• Application Number:
  US09/806,239
• Time in Patent Office: 616 Days
• Field of Search: 702/158, 702/94, 702/95, 702/105, 702/150-154, 73/17.5, 73/17.9, 73/18.1
• US Class Current: 702/158
• CPC Class Codes: B65G 63/004 for containers
• CPC Class Codes: B66C 13/46 Position indicators for suspended loads or for crane elements

Abstract

A horizontal reference marker and method of using the horizontal reference marker to determine the exact position on the ground of a ground slot for a standard freight container. At least two horizontal reference markers are fixed to the ground or any substantially horizontal stacking surface and arranged in a known position relative to a ground slot on the ground. The horizontal reference markers are shaped suitable for detection by laser means mounted on container cranes. The advantage is precise and parallel positioning of a container placed on the ground, which ensures that container stacks have sufficient clearance between them and simplifies container handling.

Claims

1. A method for measuring a distance between a traveling part of a crane and one first side of a ground slot for a container with the use of at least two horizontal reference markers, wherein two or more horizontal reference markers are fixed perpendicular to a substantially horizontal surface and arranged in a known position relative to the first side of the ground slot for the container on said horizontal surface, and by the steps of:

measuring a first distance between the traveling part of a crane and a first horizontal reference marker;

measuring a second distance between the traveling part of the crane and a second horizontal reference marker; and

calculating a distance between the traveling part of the crane and the first side of a ground slot for a container using the known distance between the first and second horizontal reference markers and the ground slot.

2. A method according to claim 1, further comprising the steps of:

calculating a third distance between the traveling part of the crane and the ground slot from the first distance and the known distance of the first reference marker from the ground slot;

calculating a fourth distance between the traveling part of the crane and the second distance and the know distance of the second reference marker from the ground slot;

comparing the third and fourth distances; and

calculating a skew of the container in respect of the first side of the ground slot from the comparison of the third distance and the fourth distance.

3. A method according claim 1, further comprising the steps of;

measuring a distance between a traveling part of the crane and a third reference marker; and

calculating from a known distance of the third reference marker from a second side of the ground slot the distance of the traveling part of the crane from the second side of the ground slot, which second side is perpendicular to the first side of the ground slot.