What do these do on my camera?

[Fabianweso]

I'm not sure what these sliding things are for. They look like the lift the bellows slightly? It's an improved Seneca view.

[Louis Pacilla]

I'm not sure what these sliding things are for. They look like the lift the bellows slightly? It's an improved Seneca view.

They are or supposed to keep the bellows from sagging or entering into image area when extended and activate as the bellows are extended but the leather strap connecting the bellows to the hardware must be supple & strong not dry or brittle or the leather strap simply snaps.

[martiansea]

I have one of these cameras, it's specifically for when the standards are very close together for wide angle shots. The idea is you stretch that out and it's supposed to make movements easier or whatever, and also as Louis said, to keep it from sagging when stretched. Specifically on this camera, the ribs inside the bellows are at least twice as thick in this area, I assume to accommodate this.
With the old bellows on mine, it would try to stretch them so tight they were almost tearing off the frame. Now that I'm replacing the bellows, I'm going to remove these, because they're not useful to me (not going to shoot 8x10 at such extreme wide angle to need it), and I don't want to worry about how to attach them to the new bellows without causing light leaks. The original ones are riveted in, and one of them had broken the leather attachment point and became useless.
Interesting idea, but I don't think it holds up too well after 100 years.