This page contains detailed instructions and screen shots for use with the article:
To run the examples provided in the article, you need to download the Loop program first. The T-loop files that are used in the following examples are included with the Loop program. They are the files tloop1.llp and tloop2.llp.
Start the Loop program and follow these instructions to activate the T-loop:
1. Select File > Open... from the program's menu. The Open dialog box appears.
2. Select the Tloop1.llp file and click Open. The T-loop will be displayed:
3. Select View > Options... to open the Options dialog box.
To view the values of the forces and moments at the two brackets, select Edit > Force... or click on the Force button on the Toolbar. The Edit Force dialog box will open. Click on Set to Zero and then close the dialog box, to return the loop to the non-activated state.
As shown above, only a force is applied to the free-end of the wire, in order to bring it to the right bracket. Notice that the free-end of the wire is not parallel to the bracket slot. The angle between the wire and the bracket slot is displayed if you select Edit > Wire Info.
Change the Slot / Point / Angle option back to Slot and activate the loop by clicking on Run:
Larger forces and moments are produced by this loop. The much larger than expected forces are due to improper preactivation, which results in constriction of the loop at the neutral position. Let's see what the neutral position looks like:
Notice how the free-end of the wire moves away from the right bracket. This is not what we want, if our purpose is to increase the moment applied by the loop without increasing the force. We can arrive at the proper preactivation shape by starting in the opposite way, i.e. from the ideal neutral position. At the ideal neutral position, the shape of the loop should be identical to the shape of the non-preactivated T-loop. As explained in the article, the required activating moment is 980 gf.mm. Therefore, the preactivated shape is arrived at, by using the following procedure:
This is the required preactivated shape.
Please read the Help file of the Loop program to learn how to use the Plier, Cutter and Spool tools to design loops of any shape. If you need further assistance, please send an email.