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Browse Prior Art Database

Pneumatic Photoelectric Transducer

IP.com Disclosure Number: IPCOM000077613D
Original Publication Date: 1972-Aug-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 64K

Publishing Venue

IBM

Related People

Beistle, RG: AUTHOR

Abstract

This transducer is for sensing the position of the tape loop in the vacuum column pneumatic buffer of a magnetic tape unit.

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Pneumatic Photoelectric Transducer

This transducer is for sensing the position of the tape loop in the vacuum column pneumatic buffer of a magnetic tape unit.

Transducer 23 is connected to back wall 43 of a vacuum column, as shown in Fig. 1. Transducer 23 includes an opaque housing formed by mating members 31 and 32. Members 31 and 32 form a closed cavity 33 within the housing. Cavity 33 includes a generally flat wall 34 and an oppositely disposed v-shaped wall 35 having a large radius at apex 70. The two diverging walls which form curved wall 35 terminate at 36 and 37 and are closely spaced to flat wall 34 at points 36 and 37. Cavity 33 is completed by two parallel triangular shaped walls 39 and 40, best seen in Fig. 2 which is a view taken along line 4-4 of Fig. 1. A light source 48 and a photocell 49 are mounted within member 31 and communicate with cavity 33 by way of tubular bores 51 and 52. The housing and bores 51 and 52 are formed so that light from source 48 is not directly communicated to photocell 49. Loosely positioned within cavity 33 is a movable member 45. Member 45 is air-impervious and flexible.

Wall 34 includes an air flow port 41 which connects that wall of cavity 33 to ambient atmospheric pressure. Portion 31 includes a second air flow port 42 which connects cavity wall 35 to wall 43 of the vacuum column. The top end of the vacuum column is subjected to atmospheric pressure, and the bottom end is connected to a vacuum source. Tape loop 44 is at a position below transducer
23. Thus, ports 41 and 42 are both connec...