US3690589A — Tape end detection device for tape recorder

Claim 1

Independent Claim 324 words

A tape end detection device for a tape recorder having a shaft and a reel, said device comprising a cylinder of an electrically insulating material secured at one end of the shaft rotatable together with the reel, a conductor having a middle annular portion and first and second protrusions respectively provided laterally on each side of the middle annular portion and being in the same peripheral plane as the middle annular portion, said conductor being provided on the outer peripheral surface of the cylinder, each of said protrusions having a width smaller than the spaces between adjacent protrusions on each side of the middle annular portion, said first and second protrusions on each side of the middle annular portion being in alternate relationship with each other in the transverse direction, three brushes contacting with the middle annular portion and the protrusions respectively, a first brush of said three brushes contacting the first protrusions, a second brush contacting the middle annular portion, and a third brush contacting the second protrusions, a first switch means including the first and the second brushes, the first protrusions and the middle annular portion, a second switch means including the second and third brushes, the second protrusions and the middle annular portion, a power source, a first capacitor connected to the power source through the first switch means, said first capacitor being adapted to be charged intermittently from the power source through the first switch means and to be discharged through the second switch means during rotation of the reel, a second capacitor connected in parallel to the first capacitor through the second switch means, said second capacitor being adapted to be discharged while said first capacitor is intermittently charged through the second switch means, and a detection output means connected to said second capacitor, with said detection output means being adapted to be operated when its terminal voltage falls below a pre-determined voltage by discharging of said second capacitor.

Claim 2

Dependent Claim 324 words

A tape end detection device for a tape recorder having a shaft and a reel, said device comprising a cylinder of an electrically insulating material secured at one end of the shaft rotatable together with the reel, a conductor having a middle annular portion and first and second protrusions respectively provided laterally on each side of the middle annular portion and being in the same peripheral plane as the middle annular portion, said conductor being provided on the outer peripheral surface of the cylinder, each of said protrusions having a width smaller than the spaces between adjacent protrusions on each side of the middle annular portion, said first and second protrusions on each side of the middle annular portion being in alternate relationship with each other in the transverse direction, three brushes contacting with the middle annular portion and the protrusions respectively, a first brush of said three brushes contacting the first protrusions, a second brush contacting the middle annular portion, and a third brush contacting the second protrusions, a first switch means including the first and the second brushes, the first protrusions and the middle annular portion, a second switch means including the second and third brushes, the second protrusions and the middle annular portion, a power source, a first capacitor connected to the power source through the first switch means, said first capacitor being adapted to be charged intermittently from the power source through the first switch means and to be discharged through the second switch means during rotation of the reel, a second capacitor connected in parallel to the first capacitor through the second switch means, said second capacitor being adapted to be discharged while said first capacitor is intermittently charged through the second switch means, and a detection output means connected to said second capacitor, with said detection output means being adapted to be operated when its terminal voltage falls below a pre-determined voltage by discharging of said second capacitor.

Claim 3

Dependent Claim 98 words

The tape end detection device for a tape recorder as defined in claim 1 wherein said detection output means includes a first transistor having a base connected to the second capacitor and to the second switch means and being in a non-conductive state when said second capacitor is discharged through said first transistor and its base voltage falling below a predetermined voltage, a second transistor having a base connected to the output of the first transistor and to the power source through a resistor, and being in a conductive state by the non-conductive state of said first transistor.

Claim 4

Dependent Claim 106 words

The tape end detection device for a tape recorder as defined in claim 2 wherein said detection output means further includes a detection output part connected between the output of the second transistor and the power source, said detection output part having a relay actuated by conductance of said second transistor and a plunger for changing the mode of the tape recorder, said plunger being actuated by closing of a circuit to the power source by said relay, and change over switch closed at the starting time of the tape recorder and being changed by action of said detection output to open said detection output part.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1975-09-12	1976-03-13	1976-09-12	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1979-09-12	1980-03-13	1980-09-12	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1983-09-12	1984-03-13	1984-09-12	$7700.00	Window Closed / Lapsed

Tape end detection device for tape recorder

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