Inflatable Safety Devices Braille Typewriters Carbon
Today on "how it's made"... Inflatable safety devices... Braille typewriters... And carbon-fiber cellos. They're designed to keep your head above water. Inflatable safety devices activate in seconds to buoy you up and keep you afloat until help arrives. You'll find these survival devices on airplanes and boats. Even when they're not inflated, they provide piece of mind that you'll be safe while on the water. To make a life vest, a computer-controlled knife cuts a pattern in urethane-coated nylon. Heat from the blade makes some pieces stick together, so a worker peels them apart. The shiny side is the waterproof coating. It'll be on the inside of the life vest. They place the front of the vest on a vacuum table to hold it down. Then they silk-screen the amount of carbon dioxide needed for inflation onto the fabric. Next, they pull an oral inflation tube through a precut hole... And then place the assembly under a radio-frequency press. It emits energy that heat-seals the tube to the fabric. They fasten the back and front vest pieces on pegs to align them. She slides the table with the vest pieces under a big radio-frequency press. Again, electromagnetic energy bonds the plastic pieces. This vest has been put together without a single stitch. The cylinder that contains the carbon dioxide has been installed. It holds about one ounce of the gas under pressure, which will instantly inflate the vest with one tug on a tab. It also activates automatically when immersed in water. A little tablet inside dissolves, triggering a spring that punctures the cylinder. Pull the cord on this pack, and you'll have an instant lifeboat, complete with a roof. To make one, the computerized blade cuts shapes out of rubberized fabric, while a plastic film helps hold it in place. They brush on a rubber adhesive to seal the boat's joints and press rubber tape over the glue. They remove air bubbles. It will take several days for the bonding to be complete. They apply the same rubber adhesive to all the inflation valves and pressure tubes. To help activate the glue, they wipe it with a damp rag, then insert a valve through a hole in one of the raft's air chambers. They apply more glue to the outside around the valve and secure it with a ring called a doubler. It really is the glue that holds everything together. They apply more rubber adhesive onto the lower inflated chamber. Then they stretch a sheet of rubber flooring over it. They smooth down the edges, again, to remove air bubbles. They run rubberized tape around the rim. It will protect it and also act as a hinge between the floor and the upper air chamber, which will go on next. In preparation for that, they measure to align all the inflation valves. Then they pull the upper air chamber, the walls of the raft, on top of the floor and lower chamber. They line up the valves but hold off on connecting them. Next, they pump regular air into the upper chamber to test the shape and function. A plastic strip has been keeping the glued surfaces from contacting. They pull it out and push down to initiate contact. Before they pack up the raft, they take stock of the survival kit. There's the first-aid package... Miniflares... Food rations... A pocketknife... And bags of water. There are enough supplies to keep you safe and fed while you wait for help to arrive. A braille typewriter types raised dots using the braille system. It's based on six dots arranged in a rectangle, three dots high by two dots across. This is called the braille cell. Different configurations of dots within this cell represent different letters of the alphabet, numbers, and punctuation marks. A braille typewriter has a spacebar in the middle and six keys, one for each dot of the braille cell. Pressing a key makes a pointed steel rod, called a stylus, type a raised dot. To build a braillewriter, they first position the six styli one by one in a carriage with steel spacers in between. The spacers ensure the styli move freely. A cover plate seals the back of the carriage, and what's called a stripper plate closes the top. The plate has six holes in the configuration of the braille cell. When you press a key, the corresponding stylus protrudes and strikes the paper against a dot-shaped eye, creating a raised dot. They screw the die to the carriage top but don't install it in the machine just yet. This is how the carriage and die will meet once it's in place. They start connecting the components which move the various styli. The first part is a steel cam rod. One end of it has a little eyelet called a lug. They put a pin in it, then slip that pin through holes in the prongs of a metal strip called a link. Later, they'll connect the other end of the link to a lever attached to a key. The braillewriter's other components are made of cast aluminum. The left end plate covers the left side of the machine. To that, they connect the carriage tube, the cylinder on which the carriage rides, and the feed roller, the mechanism you turn to feed a sheet of paper into the typewriter, then what they call the rear support, an assembly of cam rods and links. They slide the carriage onto the carriage tube. Next, they install the drum. The feed tube transfers the paper to the drum. The drum winds it into the machine, positioning it for typing. Then the rack bar. Each tooth in it is the width of a braille cell, ensuring the carriage advances the correct distance between letters. Next, they install the chain assembly, which advances the carriage. They close off the other side of the machine with the right end plate. Now they can finish the process of connecting the parts that move the styli. So far, each cam rod connects to a link. Now they connect each link to a cam lever, then each lever to a key. Here's how it all works. You press a key... It triggers the cam lever to turn the cam rod... And push up on the stylus. The stylus strikes the paper against the die yet to be installed, producing a raised dot. There's still one more paper-feed component to install--  the pressure roller. It holds the sheet of paper against the feed tube. Now they screw the die to the carriage top and install that on a support beam. Then they position this assembly over the stripper plate at the top of the carriage. They check and adjust the paper hold tension. The back plate has slots for the two levers that adjust the margins. The apron goes below the keys, the front plate above them. Then the last component, the carriage lever. When you type to the end of a line, you push this lever to the left to return to the left margin. You also push a key on the far left to advance the paper to the next line. Typing on a braillewriter is an embossing process, so you have to use thick paper. You push single keys and combinations of keys to produce different configurations of dots, each signifying different letters of the alphabet. This cello is made of carbon fibers instead of traditional wood. Enthusiasts believe this newer carbon version has a more powerful sound than the wooden instrument. It still has that characteristic sweetness, but it's more likely to be heard in the orchestral din. And, after all, every musician wants to be heard. The carbon cello was the idea of a boston symphony cellist who noticed waves resonate loudly against carbon-fiber boats. They cut the top piece of the cello out of fabric that's woven with carbon strands. This material is stronger than steel, yet electric shears easily cut through it. A worker cuts out numerous top cello pieces and then sets them aside while he works on another section of the instrument. He brushes special resin onto a fiberglass mold of the cello's back, ribs, and neck. The mold has been prewaxed to keep the resin from sticking to it. The idea is to saturate this big piece of carbon fabric with the resin as he tucks it into the curves of the mold. He smoothes it down to get rid of any bubbles that could affect the cello's tone. He brushes more resin onto the other side of the fabric, making sure it gets into all the crevices. He sponges away any surplus and then layers more fabric and resin as he builds a laminated carbon-fiber shape. He covers the layers with nylon-like material and trims the edges of the carbon fabric. Next, he places perforated plastic on the nylon and piles absorbent batting on top of that. He installs a vacuum pump and drapes a big plastic vacuum bag over everything... Then activates the vacuum. It sucks out the air and any excess resin. The perforated plastic controls the amount, and the batting absorbs it. While it's still under vacuum, they put the whole thing in an oven to bake the carbon-fiber layers together. After they peel away the batting and plastic, it comes out looking like this. The plies have fused together, and the shell has a sleek look to it. They laminate the cello's top piece in a mold and bake it until it's also hard. Using a band saw, they trim off the ragged edges and sand them for a smooth finish. Now they clamp the cello top piece onto a fixture that has stencils on the back. With a router, they cut out the stencil shape. The sound will eventually emanate from these f-holes, as they're called. They attach the company's label with glue to the inside of the cello's back section. Then they glue around the top inner rim of the cello. They tape the back tightly in place while it hardens. Next, they glue the laminated carbon fingerboard to the neck of the cello. They drill holes into the pegbox and insert the pegs which are used to tighten the strings. Soon, this cello will be more than just a shell. Coming up, we reveal its inner workings. The story of this cello has many layers. They're all carbon, and now the layers have hardened into the shape of a concert instrument. At this point, you can't make music with it, though, because they have yet to construct the inner workings, a process that is another demonstration of fine craftsmanship. The cello frames need a bit of bodywork. They rough them up with sandpaper... Then spray on a polyurethane clear coat to protect the surface. Then it's over to the string specialist, called a luthier. He sets a roughly cut wooden bridge on top of the cello and takes measure of the position. The placement of this bridge needs to be exact because its job is to elevate the strings and transfer their vibrations to the instrument. If its position is a bit off, the cello's sound will also be a bit off. Using a grease pencil, he maps out the position of the bridge between the f-holes, then sets it aside. Now he slips the wooden sound post into one of the f-holes and wedges it between the front and back of the cello. The sound post is crucial. It will strengthen the cello and couple the strings' vibrations between the front and back of the instrument. This is delicate and highly skilled work. He measures to determine if the sound post is on the mark. If it's off by even a fraction of an inch, he adjusts it a bit more. Afterwards, he double-checks the bridge's positioning. Then, with a red grease pencil, he colors over the spots where the feet of the bridge are to sit. He presses the bridge's feet into the grease marks, and this makes red smears on the feet. The smears tell him where to shave the wood so that it will fit perfectly on the top of the cello. The bridge doesn't get glued down. It's held in place only by the pressure of the strings. Next, he makes pencil marks on both tips of a measuring stick. He leans the stick against the bridge at the same angle as the strings that will run over it. He then transfers the pencil marks from the stick to the top of the bridge. He rounds off the marks by penciling around a template. And then he carves the bridge down to size. He planes it down to make it thinner. With a file, he cuts grooves to cradle the strings. Now he moves to the bottom of the instrument and slides a spike called an end pin into a precut hole. The end pin will rest on the floor, steadying the cello. He lassos the end pin with plastic rope, which is attached to the tailpiece, and he rests the tailpiece on the belly of the cello. He pulls the steel strings from the pegs and hooks them onto the tailpiece. Like most classical string instruments, the cello has four strings. Now he slides the strings into the grooves on the bridge. He turns the pegs to tighten the strings. The strings push down on the bridge, holding it in place. He tunes the cello, and now it's ready for a real performance.