Bottom Block Loose?

[bobgaggle]

Loading into a new rental space for our summer show, and as I was operating the linesets I realized the bottom block for the purchase line was loose in its tracks. If the lineset was pipe heavy, when the purchase line was locked the weight on the pipe side of the system would pull up the arbor because the bottom block would just float. The only thing holding that block down is its own weight, it wasn't bolted tightly to the T track. I expressed my concern to the house guy and he said the choice to leave those loose was intentional to act as a "shock absorber". The logic of that seems idiotic to me, and the only reason I can think of is that the installer didn't want people trying to slow the lineset with the rope lock. Rather the installer wanted the operator to grab the inside side of the purchase line to slow a pipe when it was flying in.

Anyone else ever experience this? I think Texas scenic did the install.

 

[venuetech]

It is a tension block (aka floor block) it is designed to be loose. Back when the purchase line was made of hemp or manila the length of the rope would change with the conditions. A design professor that I had said he could watch the blocks move when a sudden rain storm passed by, changing the humidity.

The rope lock should only be used for holding the balanced load in place, NEVER to slow a moving or unbalanced lineset.

 

[BillConnerFASTC]

The tension or welch block should lock by gripping the T or J guides. When it is pulled upward, the guide should bite a little. The tab on front is to step on to release it to float - to retention and to take a bite of rope so you can turn to see the stage.

With synthetic ropes there is no need for a tension block to float except if you do want to be able to take a bite on the rope. Since this is not common in high schools I have designed some projects with fixed tension blocks.

When not fixed I use a hard rubber guide instead of umhw so it will lock into Ts.

 

[tprewitt]

If the block slips when pulling the rope something isn't right. Common problems are that the tension block is installed upside down or someone has lubricated the T-track. Post a picture and we maybe able to help identify the problem.

-Ty

 

[BillConnerFASTC]

If the block slips when pulling the rope something isn't right. Common problems are that the tension block is installed upside down or someone has lubricated the T-track. Post a picture and we maybe able to help identify the problem.

-Ty

Good point. Showed up at a new install and the shoes were assembled wrong on H&H blocks causing this.