THE VIDEO CASSETTE
Find a need and fill it is an axiom often used to explain the success of a product. When Sony developed a new market with the portable reel-to-reel video recorders one thing became obvious to them. Electronic news gathering and the television broadcast industry was a market wide open for new products. Portability became the hot new sales tool for showing television sponsors that the stations and networks were on top of the news, sports and special events.


Sony was the first to develop and exploit this area. They gained an immediate upper hand and reaped great benefits from having the "first mover advantage" in the marketplace. The smaller size of the reel-to-reel recorder made it easy to carry from event to event. It was good but when Sony introduced the cartridge video recorder, the U-matic, things really began to take off. There was virtually no competition in this field and they owned the new technology outright. If any manufacturer wanted to participate in this new easy-to use-field (and there were many) they had to license the technology from Sony. Because the fully enclosed cassette design became such a hit it made Sony the leader in the broadcast video industry. Up to then they had introduced compact transistor radios, audio tape recorders and televisions mainly to the public, but now they had introduced a new standard for video recording. In the photo above we see on the left a Sony engineer demonstrating an early version of the U-matic recorder. In front and center is a semitransparent U-matic cassette and you can see how the two reels inside nested together to save space. The recorder pictured at the top is one of the later designs that sported all the bells and whistles found on the most expensive studio models. Click on the photo and we can see the interior of one of these units and explore how Sony made cassette recording possible. If you ever looked inside of an early Betamax or explored my Website you will notice some very familiar territory here. We are looking down into the U-matic with the top cover removed. In the upper left corner is the main drive motor. In the center are the video drum and tape threading ring. Click on the photo again and here we see the overall tape handling assembly. At the bottom center are the supply and take up reels. If your familiar with the Betamax you will notice that they are reversed in the U-matic. The tape travels in the opposite direction to the Beta format. Also notice the long extracting arm that pulls the tape into the threading ring. The tension arm is also on the opposite side from the Beta in the U-matic. The next photo shows the tape being extracted from the cassette. It is about to be pulled into the path of the threading ring and wrapped around the video drum and captured by the pinch roller. The tape guides that position the tape around the path are indicated. The next picture shows the tape completely threaded into the tape path. Click the picture again and the cassette door opening is visible. The next picture shows on the left is one of the video heads located on the disk assembly (upside down). On the right in this picture is the supply reel. Notice the copper colored band wrapped around it. It has a thin strip of felt glued to it that rides up next to the surface of the reel. The band attaches at one end to a stationary peg and the other end is mounted to an arm that is free to move in relation to the tension being place on it by the video tape (as it comes out of the cassette). It works by loosening and tightening the band on the reel as the tapes moves out into the path thus maintaining a steady regulated back tension on the tape. The amount of tension can be regulated by a spring that pulls against the arm itself. The next photo shows four component areas. The upper left is the photocell assembly that senses the end and beginning of the tape on the reels. A clear leader tape at the ends lets a tiny light shine through when it passes by which triggers the stop mode. This stops the tape movement when the tape reaches the end or the beginning. The photo in the upper right is the photocell arrangement from a different direction. In this U-matic only one photocell was used, some had two. The lower left photo is a close up of the pinch roller, capstan and the audio/control head. The photo at the lower right is of the video drum. Click the photo and here we see a comparison in size of drums for the Beta and U-matic formats. The smaller upper drum is Beta. Here may be a good time to mention also that U-matic was a 3/4 inch tape width and Beta is 1/2 inch. Click the photo again and here is a split shot of two types of switching sensors. To reproduce a picture recorded with two spinning video heads the picture must started at the proper time. This photo shows two types used. One the left is a metal blade that passes over a magnetic pick up and on the right is a coil (under the copper colored disk) that senses a tiny magnet passing over it. The next photo is of the underside of this U-matic unit. Here we see the belt arrangement that drives the threading ring, capstan, drum and tape reels. The metal bar going across the center is to keep the frame rigid. The next photo shows a magnetic coil located under the video drum. This coil is a brake that regulated the precise rotation speed for the drum. As with Beta to come later a single large motor would drive all the moving components during recording and playback (threading and unthreading used separate motors). Since the video heads need to be kept turning at a constant speed to create a steady picture Sony developed a system that turned them slightly faster than was required. The brake you see here would then be used to slow them down slightly and lock them in at the correct turning speed. The belt that was turning the head drum was designed to allow some slipping so the breaking action could take place. Later this system was abandoned and the video drum would have it's own motor. The entire design of the U-matic was developed by Sony and the much of system was covered by patents. Many manufacturers other than Sony entered this new recording field and under Japanese laws they were able to license this technology for the own use (by paying royalties). This is something that was good for Sony but probably didn't make them real popular with some other unit makers. This disapproval would show up later when Sony introduced home video recording and this will be covered in a later discussion. The next photo shows some of the models and the logos used, all were required to use the "U" within their name. The next photo shows some Sony U-matic units. And the last photo in this set shows a couple of late U-matic units that were made with tuners, allowing regular television reception. To got to the next panel "First Home Unit" click here.