JPS6023791Y2 - tape recorder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tape entrainment detector in a tape recorder.

Conventionally, in order to detect when a tape is wound around a capstan in a tape recorder, the rotational direction of the take-up reel base is reversed when the tape is wound around the capstan, and this reversal is detected. Tape entanglement was detected.

However, with this method, two rotation speed detectors with a 90° phase difference or a DC generator are required to detect the rotation direction of the take-up reel table, and these rotation direction detectors are complicated and expensive. However, it also had the disadvantage of worsening the space factor.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional drawbacks and to provide a tape recorder equipped with a simple, inexpensive, and space-efficient tape entrainment detection means.

The details of the present invention will be explained below with reference to the drawings for one embodiment.

FIG. 1 is a plan view of the tape deck in normal running condition, in which 1 is a take-up reel stand, 2 is a supply reel stand, and 3 is a plan view of a tape deck in a normal running state.
4 is a tape guide, 4 is a capstan, 5 is a capstan motor for driving the capstan 4, and 6 is a table.

In the running state, the tape 6 is pressed by the capstan 4 and the pinch roller 8 while contacting the head 7 and is driven in the direction of the arrow.

Figure 2 shows a state in which the tape 6 is caught in the capstan 4 for some reason, and the same parts as in Figure 1 are given the same reference numerals. A state in which several layers of tape 6 are sandwiched between 4 and pinch roller 8 is shown.

When the tape 6 is running normally, the tape tension S on the take-up side works in the direction of reducing the load torque of the capstan 4 by driving the take-up reel stand, but as shown in FIG. When the tape 6 is wound around the capstan 4, the take-up side tape tension S acts so that the take-up side of the tape 6 moves in the direction of the arrow q, thereby increasing the load torque on the capstan 4.

Therefore, the winding of the tape 6 increases the load torque of the capstan motor 5, and as a result, the load current of the capstan motor 5 increases rapidly.

Therefore, in the present invention, as shown in FIG. 3, the armature current of the capstan motor 5 (FIGS. 1 and 2), that is, the load current I, is converted into a voltage C by the load current detector 9, and the voltage comparator 10, the reference voltage e obtained by the reference voltage generator 11 is applied to the voltage comparator 10.
Compare the voltage C and the reference voltage e at the other input terminal of
By controlling the operation stop circuit 13 by the output of the voltage comparator 10, power is supplied via the stop switch 13' so that the power from the mechanism drive power source 12 is not applied to the mechanism 14 of the tape recorder.

To explain the operation of the embodiment configured as above, when the tape 6 is running normally, the load current I of the capstan motor 5 is a normal value, and the output voltage C of the load current detector 9, that is, As shown in FIG. 4, the voltage at one input terminal a of the voltage comparator 10 is approximately constant as shown in the curve shown by the solid line a, and the relationship between the voltage V and the time t is approximately constant, that is, the time t1, that is, when the tape 6 reaches the capstan. 4, the reference voltage rises rapidly when the tape is caught in the tape, and the reference voltage e
The voltage which was lower than the reference voltage e (indicated by the dotted line in FIG. 4) becomes higher than the reference voltage e due to the winding.

As a result, the output of the voltage comparator 10 increases and the operation stop circuit 1
3 is operated and the stop switch 13' is opened to cut off the power supply from the mechanism driving power source 12 to the mechanism 14 of the tape recorder, thereby stopping the operation of the mechanism 14 and preventing the tape 6 from being damaged.

As described above, according to the present invention, an increase in the load current of the capstan motor due to tape winding is detected, converted into a voltage change, and compared with a reference voltage by a voltage comparator, thereby stopping the running of the tape. Since there is no need for a rotational direction detector or the like, it can be done simply and inexpensively, and since there is no need to attach a special detector to the reel stand, the space factor is extremely good and it is effective in downsizing the tape recorder.

In the above description, a case has been described in which the mechanism is controlled to stop the running of the tape based on the output of the voltage comparator, but tape protection means such as reversing the tape based on the output of the voltage comparator may also be used.

[Brief explanation of the drawing]

The drawings are all related to the present invention; FIG. 1 is a simplified plan view of the tape deck in a normal running state, FIG. 2 is a partially omitted simplified plan view of the tape deck in a tape winding state, and FIG. 3 is an embodiment. FIG. 4 is a block diagram of the electric circuit of FIG. 4, which shows temporal changes in the voltages at the input terminals a and b of the voltage comparator 11 in FIG. 3 when the tape is wound up. 4... Capstan, 5... Capstan motor, 6... Tape, 9... Load current detector, 10... Voltage Comparator, 11...
... Reference voltage generator, 13 ... Operation stop circuit, 14 ... Mechanism.

Claims (1)

[Scope of utility model registration request] In a tape recorder that directly drives the tape by a motor directly connected to a capstan that is integrated with a flywheel, a change in the load current of the motor that occurs when the tape is caught in the capstan while running is converted into a voltage change. This voltage value is compared with a reference voltage by a comparator, and when the voltage converted into the voltage change is greater than the reference voltage, the output of the comparator controls a mechanism such as stopping or reversing the running of the tape. A tape recorder characterized by: