Method and device for maintaining a position of a load suspended from a lifting gear

• US 7,267,240 B2
• Filed: 03/29/2005
• Issued: 09/11/2007
• Est. Priority Date: 09/30/2002
• Status: Active Grant

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Schulte, Peter, Maurer, Peter
• Primary Examiner(s): Brahan; Thomas J.
• Application Number:
  US11/093,015
• Publication Number:
  US 20050224438A1
• Time in Patent Office: 896 Days
• Field of Search: 212/274, 212/275, 212/272, 212/270
• US Class Current: 212/270
• CPC Class Codes: B66C 13/063 electrical

Abstract

In a method for maintaining a position of a load on a lifting gear, a position of a load, which is suspended from a trolley of a lifting gear via at least four cables, is determined and a swinging motion of the load is counteracted by selectively adjusting the length of at least one of the cables.

Claims

1. A method for controlling a position of a load on a lifting gear, comprising the steps of:

determining a position of a load suspended from a trolley of a lifting gear via at least four cables which hold the load and terminate at four separate locations on the load; and

counteracting a swinging motion of the load by operatively connecting each of the four cables with a separate drive and selectively operating the drives to selectively adjust the length of the cables, wherein the counteracting step includes the steps of automatically ascertaining a change in tension of a cable as a result of a change in torque applied by an electric motor of the drive associated to the cable, and operating at least one of the drives in response to the change in tension of the cable to make the cable taut again.

2. The method of claim 1, wherein the drive of the cable is operated to shorten the length of the cable.

3. The method of claim 2, wherein the drives of two of the cables are operated to shorten the length of the cable.

4. The method of claim 1, wherein the drives of two other ones of the cables are operated to lengthen the cables.

5. The method of claim 4, wherein the drives of three other ones of the cables are operated to lengthen the cables.

6. The method of claim 1, wherein the drives of two diagonally oppositely disposed cable are operated to lengthen or shorten the two diagonally oppositely disposed cables.

7. The method of claim 1, wherein the counteracting step includes the step of selectively paying out or taking in the cables to maintain a horizontal position of the load during lifting, lowering or swinging motions.

8. The method of claim 1, wherein the load is defined by a skew angle between an x-axis and a centerline through the load, when out of plumb, said skew angle being influenced by changing the length of at least one of the cables.

9. A device for controlling a position of a load on a lifting gear, comprising:

a trolley;

a hoisting mechanism including at least four lifting units for suspending a load at four separate locations, each lifting unit having a cable drum which receives a cable terminating at a corresponding one of the four locations for connection to the load, and a separate drive unit operatively connected to the cable drum for adjusting a length of the cable so that a swinging motion of the load can be counteracted through selective operation of the drive units and accompanying change in length of pertaining cables and

a detection system for recognizing a change in tension of a cable as a result of a change in torque applied by an electric motor of the drive associated to the cable and controlling a position of the load by operating at least one of the drives in response to the change in tension of the cable to make the cable taut again,

wherein the detection system and the drive units of the lifting units are constructed for automatic operation.

10. The device of claim 9, wherein the cables extend between the load-carrying member and the lifting units at a slant in relation to a lifting direction of the load.

11. The device of claim 10, wherein the slant of the cable between the load-carrying member and the lifting units is greater than 90°

.

12. The device of claim 9, wherein the drive units are constructed such that each of the drive units can be controlled and regulated individually.

13. The device of claim 9, wherein the drive unit includes an electric motor.