Variable Strength Magnetic End Effector for Lift Systems

Abstract

A device and method for adjusting the magnetic strength of a magnetic end effector for lift systems is described. The magnetic end effector is capable of lifting discriminate payloads by selectively varying the strength of the magnetic forces output by the magnetic end effector. An actuator can be operatively coupled to the variable strength magnet end effector, wherein the actuator is selectively actuatable to control the adjustment of the variable strength magnet. The actuator may also be configured to maintain the variable strength magnet at a desired magnetic force output strength once achieved for any given amount of time.

What is claimed is: 
     
         1 . A method for lifting and transporting a specific number of objects from a larger collection of objects using an end effector supported about a lift system and employing an adjustable magnetic force, the method comprising:
 identifying a collection of objects arranged adjacent one another;   determining a specific number of objects to lift from the collection of objects;   positioning a continuously variable strength magnetic end effector about the collection of objects, the variable strength magnetic end effector having an infinite number of available magnetic strength outputs;   actuating the variable strength magnetic end effector to achieve a magnetic strength output above a threshold level suitable for discriminately lifting the specific number of objects from the collection of objects; and   maintaining the magnetic strength output at least at the threshold level for a given period of time.   
     
     
         2 . The method of  claim 1 , wherein the actuating the variable strength magnet comprises continuously adjusting the magnetic strength output of the variable strength magnetic end effector to determine a load weight function corresponding to the threshold level, the threshold level being realized upon the specific number of elements being lifted. 
     
     
         3 . The method of  claim 1 , wherein the actuating the variable strength magnet comprises inputting a known load weight value into a system configured for adjusting the magnetic strength output of the variable strength magnetic end effector, wherein the system matches the load weight value with a corresponding actuator function value, and wherein the system controls the actuator to adjust the magnetic output strength accordingly. 
     
     
         4 . The method of  claim 1 , wherein the actuating the variable strength magnet comprises actuating a plurality of variable strength magnets. 
     
     
         5 . The method of  claim 4 , wherein the actuating the variable strength magnets comprises actuating an adjustment mechanism associated with the plurality of variable strength magnets. 
     
     
         6 . The method of  claim 1 , further comprising adjusting the magnetic strength output to a level at least above the threshold level after the specific number of objects are initially lifted to better secure the objects to the end effector. 
     
     
         7 . The method of  claim 1 , wherein the steps of positioning, actuating and maintaining are carried out using a master control system. 
     
     
         8 . The method of  claim 1 , wherein the positioning a continuously variable strength magnetic end effector about the collection of objects comprises positioning a mobile platform unit about the collection of objects, the mobile platform unit comprising a lifting element operatively supporting the variable strength magnetic end effector. 
     
     
         9 . A magnetic end effector, comprising:
 a housing;   a magnetic element disposed within the housing, the magnetic element being continuously adjustable to an infinite number of magnetic strength output levels; and   at least one communication element that associates the magnetic element with an actuator that facilitates control of the adjustment of the magnetic element,   wherein the actuator maintains the magnetic element at a desired magnetic force strength output level to secure a lifted object to the end effector.   
     
     
         10 . The magnetic end effector of  claim 9 , wherein the magnetic element comprises a permanent magnet, and wherein the magnetic end effector further comprises: at least one ferrous block of material disposed in the housing; at least one non-ferrous block of material disposed in the housing, wherein the permanent magnet is rotatable to any number of infinitely available positions about the ferrous and non-ferrous blocks of material to generate corresponding infinite number of magnetic strength output levels. 
     
     
         11 . The magnetic end effector of  claim 10 , wherein the at least one communication element comprises a shaft coupled to the permanent magnet, and a link to a piston rod of a linear actuator, wherein the link as coupled to the shaft functions to convert linear motion of the piston rod into rotational motion of the shaft and the permanent magnet to facilitate the adjustment of the permanent magnet to achieve the infinite number of magnetic strength output levels. 
     
     
         12 . The magnetic end effector of  claim 10 , wherein the at least one communication element comprises a shaft coupled to the permanent magnet, wherein the actuator comprises a motor that operates to rotate the shaft and the permanent magnet to achieve the infinite number of magnetic strength output levels. 
     
     
         13 . The magnetic end effector of  claim 9 , wherein the magnetic element comprises an electromagnet, wherein a current to the electromagnet is continuously variable to achieve the infinite number of magnetic strength output levels.