REEL BLOCK OPERATION AND TORQUE
|
Forward back tension is controlled by the number one guide, which his also the tension lever. Back tension is adjusted several ways depending on what type of reel table mechanism is used. The dual pancake motor block uses an electronic pickup made into the number one guide. This type is shown in the upper right corner of the photo. It uses special circuitry in the machine to regulate operation. Most machines use pendulum reel design with the lever, spring and band system, shown in the center. Here the tape travels over the pin (guide one) located in the arm which loosens and tightens a band that wraps around the supply reel. This is how proper tension is maintained the on the tape as it is coming out of the cassette. The reel table being illustrated is the third design where a pancake motor is not used, the pendulum assembly is driven by a cogged belt running off of the capstan. A less costly design but yet still very effective. As you can see from the three photos stacked on the left, the guide position adjustment is performed by moving either an offset boss as in the top and middle photos, or a slide held in place by a screw as in the bottom photo. (In the middle photo the band end from the top photo is shown laying loose.) A special tool is inserted into the small hole and articulates with the toothed slide or boss to move them back and forth, this in turn positions the arm left or right. The special tools for doing this are shown in the bottom right of the main photo. In most machines they would be passed through an opening in the frame to reach the adjustment (the frame is not illustrated here). A tensioner spring regulates the actual amount of drag or back tension produced from the arm. Click on the photo to see the arm, spring adjustment and tools. Now let's look at what part the reels play in maintaining proper tension, click here. To go to TORQUE TESTING CASSETTES click here   |