Web Tension Sensor
Original Publication Date: 1973-Dec-01
Included in the Prior Art Database: 2005-Feb-27
Ellis, RE: AUTHOR [+2]
This tension sensor is useful in monitoring the web or tape tension in a reel-to-reel magnetic tape unit. It is constructed to allow empirical adjustment of the sensor to a position which achieves optimum tension sensing, as the tape's reel radius changes between maximum and minimum conditions.
Web Tension Sensor
This tension sensor is useful in monitoring the web or tape tension in a reel- to-reel magnetic tape unit. It is constructed to allow empirical adjustment of the sensor to a position which achieves optimum tension sensing, as the tape's reel radius changes between maximum and minimum conditions.
Fig. 1 shows a reel-to-reel magnetic tape unit having a pair of reels 10 and 11, a centrally located tape processing station 12, an idler roller or air bearing 13 and a second idler combined with the tape tension sensor 14. As is apparent from this figure, the tape path between sensor 14 and station 12 is fixed, whereas the tape path between sensor 14 and reel 11 changes from a maximum radius to a minimum radius as the reel empties. Ideally, sensor 14 is located to maximize distance D, and thereby render the sensor's tension output less sensitive to these changes in reel radius.
Tension sensor 14 is shown in detail in Fig. 2. Reference plates 15 and 16 define stationary support members not shown in Fig. 1. Each of these members includes an aligned opening 17 which cooperates with a setscrew 18. Each opening receives an identical disc 19, better shown in Fig. 3. The outer diameter of each disc 19 is approximately equal to the diameter of opening 17 and the disc is designed to be rotationally adjusted to a preferred position therein.
Each disc includes an annular portion 20, a stiff flexible post 21 and a centrally located roller or air bearing supporting portion 22. The post of each disc mounts two strain gages 23 and 24. These strain gages are connected in the electrical circuit shown in Fig. 4.