Tape ending indicator for tape recorder

• US 4,097,726 A
• Filed: 06/03/1975
• Issued: 06/27/1978
• Est. Priority Date: 06/11/1974
• Status: Expired due to Term

• Current Assignee: Olympus Optical Company Ltd. (Olympus Corporation)
• Original Assignee: Olympus Optical Company Ltd. (Olympus Corporation)
• Inventors: Satoh, Ken, Tomizawa, Yoshio
• Primary Examiner(s): Mautz, George F.
• Application Number:
  US05/583,267
• Time in Patent Office: 1,120 Days
• Field of Search: 242/191, 242/57, 242/75.51, 242/75.45, 242/75.44, 340/259, 340/260, 360/137, 235/151.32, 235/92 R, 235/92 A, 235/92 FQ, 235/92 CA, 235/92 PK, 235/92 V, 235/132 N, 235/92 DN, 235/92 PE, 235/92 PD, 235/92 MT, 235/92 MS, 235/92 MP, 235/92 CT, 235/92 EV
• US Class Current: 377/18
• CPC Class Codes: G11B 27/13 the information being derived from movement of the record carrier, e.g. using tachometer
• CPC Class Codes: G11B 27/34 Indicating arrangements indicating means incorporated in magazine or cassette G11B23/046 and G11B23/0875; indicating measured values in general G01D

Abstract

A tape ending indicator comprises a flip-flop circuit responsive to a pulse signal derived from a rotating tape for producing a pulse of an increased width, which is applied to one input of an AND circuit which also receives count pulses of a given, constant frequency from a suitable source. The number of count pulses which are contained in the output signal from the AND circuit is counted in order to detect a change of the count above a first value or below a second value as the diameter of the roll of the taken up tape increases or decreases, thereby indicating the ending of the tape.

Claims

1. A tape ending indicator for a tape recorder, comprising:

a rotating member operatively connected to a supply or take-up reel of a tape recorder and adapted to rotate at a speed proportional to the rotational speed of said supply or take-up reel;

a plurality of magnets mounted on and spaced at equal intervals along the periphery of said rotating member;

a magnetic head disposed adjacent to the periphery of said rotating member for generating a pulse signal each time one of said magnets passes said magnetic head;

a flip-flop circuit responsive to said pulse signal, the output of said flip-flop changing each time said pulse signal is applied thereto;

a count pulse generator for producing count pulses of a fixed frequency, the frequency of said count pulses being substantially greater than the frequency of said pulse signals generated by said magnetic head;

gate means connected to said flip-flop circuit and said count pulse generator for passing said count pulses whenever said gate means is enabled by said output of said flip-flop circuit whereby the number of count pulses passed by said gate means is proportional to the frequency of pulses generated by said magnetic head;

indicator means for counting the number of pulses passed by said gate means and for providing an indication that a terminal end of a tape is approaching when the number of count pulses passed by said gate means reaches a predetermined value.

2. A tape ending indicator for tape recorder according to claim 1 in which the count pulse generator comprises a pulse oscillator which produces count pulses of a fixed frequency.