Crane Position Indicator

Abstract

A method and apparatus for lifting loads support from a crane to eliminate swaying of the load includes providing the crane with a laser source on either side of the crane. The center of gravity of the load is marked on the load and the boom is positioned such that the laser lights projection on the ground or on surface of the load and the center of gravity of the load are aligned in a straight line.

What is claimed is: 
     
         1 . A method of correctly lifting a load by a crane comprising;
 a) marking the center of gravity of the load on top of the load,   b) projecting a pair of laser lights perpendicular to the ground from laser units on two sides of a lifting device,   c) manipulating the lifting device such that the projections of the laser lights are located on top of the load;   d) positioning the lifting device such that the center of gravity of the load is located between the projections of the laser lights; and   e) lifting the load.   
     
     
         2 . The method of  claim 1 , wherein the load is irregularly shaped. 
     
     
         3 . The method of  claim 1 , wherein the lifting device comprises a crane. 
     
     
         4 . The method of  claim 1 , wherein the laser units are pivotably mounted on the sides of the lifting device. 
     
     
         5 . The method of  claim 1 , wherein the laser units are attached at a sheave center pin. 
     
     
         6 . The method of  claim 1 , wherein projections of the laser light sources are aligned in a straight line. 
     
     
         7 . The method of  claim 1 , wherein the laser lights impinge on the load. 
     
     
         8 . The method of  claim 1 , wherein the laser light comprises a shaft. 
     
     
         9 . The method of  claim 8 , wherein the shaft of the laser light is fixedly attached to the crane. 
     
     
         10 . A method of erecting a stationary crane by a mobile crane comprising;
 a) An extensible boom which can be raised or lowered;   b) providing the mobile crane with a laser light source;   c) determining the minimum and maximum radius of the boom;   d) marking the ground based on the minimum and maximum radius of the boom from a ground point of the mobile crane; and   e) positioning the extensible boom such that laser light remains within the maximum and minimum radii of the boom.   
     
     
         11 . The method of  claim 10 , further comprising determining a safe operating range of the mobile crane comprising a minimum radius from the crane's footprint and a maximum radius from the crane's footprint. 
     
     
         12 . The method of  claim 10 , wherein the positioning further comprises maintaining the projections between the minimum radius and the maximum radius when lifting the load. 
     
     
         13 . The method of  claim 10 , wherein the extensible boom is a telescoping boom. 
     
     
         14 . The method of  claim 10 , wherein the mobile crane is comprises two laser light sources. 
     
     
         15 . The method of  claim 10 , wherein one or more of the laser lights comprises a laser light assembly. 
     
     
         16 . The method of  claim 15 , wherein the laser light assembly includes a switch positioned within a hollow cylinder. 
     
     
         17 . The method of  claim 15 , wherein the laser light assembly comprises a housing portion, wherein the housing portion is rotatably supported on a shaft. 
     
     
         18 . The method of  claim 15 , wherein the laser light assembly comprises a battery. 
     
     
         19 . The method of  claim 17 , wherein the laser light assembly comprises a weighted arm extending outwardly from housing. 
     
     
         20 . The method of  claim 19 , wherein the weighted arm extending from the housing portion of the laser light assembly comprises a battery.