If practice makes perfect but noone is perfect, then why practice.
*** This post was edited by Boz 11/8/2003 11:24:06 PM ***
*** This post was edited by Boz 11/8/2003 11:24:19 PM ***
There are a few different basic types of brakes.
First, and probably simplest, are the Arrow-type brakes. The brake caliper is basically a U-shaped metal frame, inside are two brake pad carriers. On each, a leaf spring holds the brake pad back against the outside of the frame. Between the frame and the brake pad is an airbag...it looks like a piece of fire hose, with one end sealed shut and an air line attached to the other. Apply air, and the airbag inflates, forcing the brake caliper inward. When the air valve opens, the leaf spring pulls the brake pad back, forcing the air out of the airbag.
At some point, Arrow re-designed that brake, changing the design so that the brake pad is cantilevered, held closed by eighteen small coil springs, nine on each brake pad, and the airbag is used to push the brake open. I've seen the cantilevered brakes on Big Bad Wolf, and on the mine train at Six Flags St. Louis.
Most of the other brakes you see use a spring-loaded pneumatic piston to drive a mechanical linkage which rotates a cam to move the brake pads together or pull them apart. Typically the spring is inside the cylinder, so all you see is the rod end coming out, which hooks to the cam. A cam is used so that the single piston can simultaneously move the pads on both sides of the caliper.
Come to think of it, I think most cam-operated brakes have two cylinders, one at each end...but the cam mechanisms are duplicated at the ends of the brake. It isn't one for each pad.
Then there are skid brakes...these come in two varieties. The manually operated ones have a long lever which operates a cam which pushes the brakes up when the lever is pulled. Air operated ones replace the long lever with a pneumatic cylinder. In some cases, a weight is used to cam the brakes up, and a cylinder is used to pull them down again.
Does that help? :)
--Dave Althoff, Jr.
Who can tell you how brakes work, but who can't get his furnace working.....
I am one.
I am Turbo.
Top Thrill in the front row... anything else is lame
--Dave Althoff, Jr.
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