Write ring detector for magnetic recorders

Claim 2

In a recording apparatus of the type having a write mode and a read mode and wherein the presence of a write indicator is detected to enable the write mode and said write indicator is a write ring inserted into an annular groove in a magnetic tape reel to enable the write mode, the combination comprising: a. a reflective surface which occupies a first position when said write indicator is present and a second position when said write indicator is not present, said reflective surface secured to a movable portion of a hub assembly onto which said magnetic tape reel slidably mounts, such that said movable portion abuts against said write ring to cause said reflective surface to occupy said first position; b. means for illuminating a portion of said reflective surface when it occupies said first position; c. sensing means responsive to light reflected from said reflective surface to produce an electrical signal; and d. circuit means responsive to said electrical signal to produce a write enable signal.

Claim 3

In a recording apparatus of the type having a write mode and a read mode and wherein the presence of a write indicator is detected to enable the write mode and said write indicator is a write ring inserted into an annular groove in a magnetic tape reel to enable the write mode, the combination comprising: a. a reflective surface which occupies a first position when said write indicator is present and a second position when said write indicator is not present wherein said reflective surface is secured to a movable portion of a hub assembly onto which said magnetic tape reel slidably mounts, such that said movable portion abuts against said write ring to cause said reflective surface to occupy said first position; b. means for illuminating a portion of said reflective surface when it occupies said first position; c. a first phototransistor sensitive to light reflected from said reflective surface to produce an electrical signal; and d. circuit means responsive to said electrical signal to produce a write enable signal, said circuit means comprising e. a first transistor coupled in series between positive and negative voltage supplies, with the base terminal thereof coupled to the collector terminal of said first photo transistor, and f. a second transistor coupled in series between a positive voltage supply and a reference potential, with the base terminal thereof connected to the emitter terminal of said first transistor and wherein the circuit output is taken from the collector terminal of said second transistor, whereby g. illumination of threshold intensity directed upon the base of said photo transistor will bias said first transistor on and said second transistor off, thereby producing a logic one circuit output signal.

Claim 4

In a recording apparatus of the type having a write mode and a read mode and wherein the presence of a write indicator is detected to enable the write mode and said write indicator is a write ring inserted into an annular groove in a magnetic tape reel to enable the write mode, the combination comprising: a. a reflective surface which occupies a first position when said write indicator is present and a second position when said write indicator is not present wherein said reflective surface is secured to a movable portion of a hub assembly onto which said magnetic tape reel slidably mounts, such that said movable portion abuts against said write ring to cause said reflective surface to occupy said first position; b. means for illuminating a portion of said reflective surface when it occupies said first position; c. a first phototransistor sensitive to light reflected from said reflective surface to produce an electrical signal; and d. circuit means responsive to said electrical signal to produce a write enable signal, said circuit means comprising e. a first transistor coupled in series between positive and negative voltage supplies, with the base terminal thereof coupled to the collector terminal of said first photo transistor, and f. a second transistor coupled in series between a positive voltage supply and a reference potential, with the base terminal thereof connected to the emitter terminal of said first transistor and wherein the circuit output is taken from the collector terminal of said second transistor, whereby g. illumination of threshold intensity directed upon the base of said photo transistor will bias said first transistor on and said second transistor off, thereby producing a logic one circuit output signal.

Claim 5

In a read/write magnetic recording apparatus, the combination comprising: a. a turntable secured to a rotatable shaft which is coupled to be rotated by a motor; b. a hub assembly secured to said turntable, said hub assembly being comprised of a fixed portion and a movable portion; c. a reflective surface on said movable portion of said hub assembly; d. a magnetic tape reel slidably mounted onto said fixed portion of said hub assembly, said tape reel having an annular groove therein; e. a write ring inserted in said annular groove to select a write mode of operation, and abutting said movable portion to cause said reflective surface to occupy a predetermined position; f. an incandescent light source positioned to direct a light beam to said predetermined position; and g. sensor means positioned to receive light reflected from said reflective surface at said predetermined position and produce a write enable signal.

Claim 6

In a read/write magnetic recording apparatus, the combination comprising: a. a turntable secured to a rotatable shaft which is coupled to be rotated by a motor; b. a hub assembly secured to said turntable, said hub assembly being comprised of a fixed portion and a movable portion; c. a reflective surface on said movable portion of said hub assembly; d. a magnetic tape reel slidably mounted onto said fixed portion of said hub assembly, said tape reel having an annular groove therein; e. a write ring inserted in said annular groove to select a write mode of operation, and abutting said movable portion to cause said reflective surface to occupy a predetermined position; f. an incandescent light source positioned to direct a light beam to said predetermined position; and g. sensor means positioned to receive light reflected from said reflective surface at said predetermined position and produce a write enable signal.

Claim 7

The combination of claim 3 wherein said sensor means is a photo transistor.

Claim 8

The combination of claim 4 further comprising circuit means coupled to the output terminal of said photo transistor to produce a logic write enable signal when illumination of a threshold intensity is detected by said photo transistor.