JPH0430656B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a tape end detection device for a tape recorder that operates an operating section when a reel shaft on the tape winding side stops.

[Technical background of the invention and its problems]

In a so-called reverse tape recorder, a pair of reel shafts are used alternately as the tape winding side and the tape supply side, and playback or recording can be performed when the tape runs in either direction. In order to operate a switching mechanism that switches the running direction of the tape when the tape is wound, or to operate an automatic stop mechanism, it is first necessary to detect that the tape has been wound to the end. Conventionally, one way to do this is to detect the rotation of one reel shaft, and when that reel shaft stops, it is assumed that the tape has been wound to the end, and actuating parts such as a switching mechanism or an automatic stop mechanism are activated. It was

However, according to this, each time the tape running direction is switched, the reel shaft on the rotation detection side becomes the tape winding side and then the tape supply side. If the reel shaft on the rotation detection side is on the tape supply side and the tape becomes slack, or for some other reason the reel shaft on the tape supply side is temporarily stopped, There was a drawback that malfunctions occurred, such as the actuating section operating even though the tape had not been wound to the end.

This kind of malfunction occurs when the reel shaft on the rotation detection side becomes the tape supply side.
It would be sufficient to always detect the rotation of the reel shaft on the tape winding side. This is because the reel shaft on the tape winding side is driven by the drive source, so it is unlikely that the reel shaft will stop due to tape slack or the like. However, no tape end detection device based on this concept has been successfully put into practical use.

For example, the device described in Japanese Unexamined Patent Publication No. 139347/1983 is also considered to be a good example of failure. As shown in FIG. 1, the reel stands 25 and 43 are provided with cams 35 and 46, respectively.
46 is urged in the same direction as the rotational direction of the reel stands by the contact resistance between each reel stand 25, 43, and a detection cam 2 is provided on one reel stand 25 side coaxially with this.
2 is provided, and this detection cam 22 and the other reel stand 4
It is connected to the cam 46 on the third side by a connecting rod 30.
Further, two guide grooves 28 and 29 in the centripetal direction are provided at one end of the detection cam 22, and a locking protrusion 27 is provided between them. and the guide groove 28 or 2
9 is a detection pin 63 protruding from the detection arm 62.
is inserted, and the detection arm 62 is inserted into the guide groove 28,
Repeat the reciprocating motion in parallel with 29. Therefore, when one reel stand 25 becomes the tape winding side, the cam 35
is biased in the rotational direction of the reel stand 25 and presses the detection cam 22 in the same direction, and the detection pin 63 reciprocates while slidingly contacting the inner edge of one of the guide grooves 28. When the other reel stand 43 is on the tape winding side, the cam 46 is urged in the rotational direction of this reel stand 43, presses the detection cam 22 in the same direction via the connecting rod 30, and the detection pin 63 Other guide groove 2
It reciprocates while sliding against the inner edge of 9. When the detection cam 22 is pressed in any direction, the locking protrusion 27 comes to escape from the detection pin 63, but when the tape is taken to the end, both the reel stands 25 and 43 stop. However, since the pressing force against the detection cam 22 disappears, the detection pin 63 comes into contact with the top end of the locking protrusion 27. As a result, the detection arm 62 rotates about the detection pin 63, actuating the interlocking mechanism 6, and as a result, the switching plate 7 moves to the right or left to switch the running direction of the tape.

However, the device described in the above publication has a serious defect. For example, suppose that while one reel stand 25 is on the tape winding side, the other reel stand 43 is temporarily stopped due to slack in the tape or some other cause. When such a situation occurs,
One cam 35 is urged by the contact resistance between it and the reel stand 25 and presses the detection cam 22, while the other cam 46 prohibits rotation of the detection cam 22 due to the contact resistance with the reel stand 43. act.
Since the contact resistance between the cam 35 and the reel stand 25 and the contact resistance between the cam 46 and the reel stand 43 should be of the same magnitude, in the end, one cam 35 is pushed. The pressure is canceled out by the resistance force of the other cam 46, and the detection pin 63 comes into contact with the top end of the locking protrusion 27, resulting in malfunction. In other words, although the device described in the above-mentioned publication aims to prevent malfunctions even if the reel stand on the tape supply side stops for some reason, this purpose has not been achieved.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a tape end detection device for a tape recorder that does not malfunction even if the reel shaft on the tape supply side stops for some reason.

[Summary of the invention]

The outline of the present invention is schematically shown in FIG. In other words, 1 alternately serves as the tape winding side and the tape supply side.
Rotation detection member b1 for each pair of reel axes a1 and a2,
b2 is provided, and the rotational force of each reel shaft a1, a2 is applied to these members b1, b2 by a friction mechanism c.
1, c2, and each rotation detection member b1,
The biasing force of b2 is transmitted to the common actuating part d, and a supply side detection member locking mechanism e is engaged with the rotation detection member (for example, b2) on the tape supply side, so that the rotation detection member b2 on the tape supply side The actuating part d is configured to be actuated when the relationship between the actuating part d and the actuating part d is cut off, and the applied force transmitted from the rotation detecting member b1 on the tape winding side to the actuating part d disappears.

Therefore, the operating portion d does not operate unless the reel shaft a1 on the tape winding side stops, that is, unless the tape is wound to the end, and malfunctions can be reliably prevented.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described based on the drawings from FIG. 3 onwards.

FIG. 3 is a schematic plan view of an auto-reversing tape recorder, and 101 in the figure is the main board. A head mounting plate 102 is mounted on the main board 101 so as to be movable up and down in the figure, and a magnetic head 103 is mounted on the head mounting plate 102. Also, on the main board 101 are a pair of left and right capstan shafts 104, 204 and a pinch roller 10.
5,205 are provided. Each pinch roller 1
05, 205 are pivotally supported by pinch arms 106, 206 rotatably supported on the main board 101.

In the figure, reference numerals 107 and 207 indicate a pair of reel shafts, and reel shaft gears 108 and 208 are provided coaxially with the reel shafts at the base of each reel shaft. In the figures, all gears are simply represented by circles (pitch circles) (the same applies to other figures, and the meshing points of the gears are marked with black dots).

In addition, 109 in the figure is the capstan shaft 104,
204 and the reel shafts 107, 207, respectively, in predetermined directions.
10 is a magnetic plunger that holds the head mounting plate 102 in the forward position (operating position).

A pinch roller switching plate 111 is rotatably supported at the front end of the head mounting plate 102 via a pivot shaft 111a, and a cam pin 112 is provided protruding from the upper surface of the front end of the switching plate 111. . Further, a central portion of a bar spring 113 is locked to the pivot shaft 111a. Both ends of the rod spring 113 are locked to the left and right ends of the switching plate 111, and are also locked to the rotating ends of the pinch arms 106, 206 on the left and right front ends, respectively.

In the figure, reference numeral 114 denotes a supply-side detection member locking plate mounted on the main board 101 so as to be movable forward and backward in the left-right direction in the figure. This locking plate 114 is provided with a cam hole 115 into which the cam pin 112 is inserted, and an engagement hole 116 that is long in the vertical direction in the figure. The front edge of the cam hole 115 is inclined toward the tip from the left and right toward the center, and the tip thereof has a recess 115a into which the cam pin 112 is fitted.
This is what has become the norm.

In the figure, 117 is the right capstan shaft 2.
04 as a fulcrum, and this switching rotary plate 117 has the engagement hole 11.
An engagement pin 118 to be inserted into the 6 is protrudingly provided, and an engagement hole 119 that is long in the radial direction is provided at the tip end.
is provided.

In the figure, 120, 220 are the respective reel shafts 107,
A rotating plate that can freely rotate around the center of 207 as a fulcrum.
Gears 121, 221 are provided on each rotating plate 120, 220.
are pivotally supported, and these gears 121, 221 are meshed with the respective reel shaft gears 108, 208. Both rotating plates 120, 220 have projections 12 on some parts.
2, 222 and tension springs 123 to each other.
is suspended and held in place by this spring 123.

In the figure, 124 indicates the polarity of the magnetic head 103.
This is a switch that changes depending on the running direction of the tape.

In addition, 125 in the figure is a switching gear, and this gear 125
An engagement pin 126 to be inserted into the engagement hole 119 is protruded from the upper surface of the engagement pin 126, and two symmetrical tooth profiles are cut out to form rest portions 125a and 125b. A reverse drive gear 127 is coaxially provided below the switching gear 125.

FIG. 4 shows the motor 109, the left and right capstan shafts 104, 204, and the reel shaft gear 1.
08, 208, in the figure 128 is the motor pulley, 129 is the main board 101
This is a driven pulley that is pivotally supported on the bottom surface. Also, 1 in the figure
30, 230 are each capstan shaft 104, 204
131 is a guide pulley that is pivotally supported on the lower surface of the main board 101. A gear 132 is integrally formed on the lower surface of the driven pulley 129. Further, in the figure, 133, 134, and 135 are integral gears, 136, 137, and 138 are other integral gears, and 139, 140, and 239, 240 are integral gears that are provided symmetrically. Further, 141, 142, and 143 in the figure are also integral gears.

And motor pulley 128 and driven pulley 129
The motor pulley 128 and the left and right flywheels 130 rotate in conjunction with each other via an endless belt 144.
230 and the guide pulley 131 are interlocked and rotated via a separate endless belt 145, and both capstan shafts 1
04 and 204 in opposite directions.

On the other hand, the rotation of the driven pulley 129 is controlled by the gear 132,
133, 134, 137, 136, 239, 24
0 and is transmitted to the right reel shaft gear 208 via the gear 221. Further, the rotation of the gear 239 is transmitted to the left reel shaft gear 108 via the gears 139, 140 and the gear 121.

Furthermore, the rotation of gears 133 and 134 is
5, 141, and 143 to the reverse drive gear 127.

Since the left and right reel shafts 107 and 207 have the same configuration, they will be explained together in one drawing (FIG. 5). The code in the 100s is the left reel axis 10.
7 side, and the code in the 200s indicates the right reel axis 2.
07 side is shown.

Shafts 147, 247 are erected on the main board 101 via bushes 146, 246.
Compression coil springs 148, 248 having a small elastic modulus, presser plates 149, 249, and friction materials 150, 250 made of felt or the like are fitted in order to 46, 246. In addition, the above-mentioned presser plates 149, 249
There are two pressing protrusions 151a, 252a,
151b and 251b are provided protrudingly. Further, the shafts 147, 247 have rapid feed gears 152, 25.
2 are fitted. This rapid feed gear 152,
252 has sleeve parts 153, 253 on the upper surface side, and compression coil springs 154, 25 with a large elastic modulus are attached to the sleeve parts 153, 353.
4. The reel shaft gears 108, 208 and friction materials 155, 255 made of felt or the like are fitted in sequence. Furthermore, the sleeve portions 153, 25
Reel receiving plates 156, 256 and cylindrical reel supports 157, 257 are firmly fitted to the outer periphery of the reel 3. Engagement rings 159, 259 having engagement portions 158, 258 that engage with the reel hub (not shown) in the rotational direction are attached to the outer peripheries of the reel supports 157, 257 so as to be movable up and down. the coupling rings 159, 259 and the reel receiving plate 156,
Compression coil springs 160, 260 are connected between 256 and 256.
is inserted. Note that the engagement ring 159, 2
The amount of upward movement of the reel 59 is regulated by the reel support 157.

Here, the compression coil springs 148, 248,
A reverse friction mechanism 161, 261 is constituted by the holding plates 149, 249, the friction materials 150, 250, and the rapid feed gears 152, 252, and the compression coil springs 154, 254, the reel shaft gears 108, 208, and the friction materials 155,255
The reel receiving plates 156, 256 constitute tape winding friction mechanisms 162, 262.

Rotation detection members 163, 263 are provided near each reel shaft 107, 207.

As shown in FIG. 6, the rotation detecting members 163, 263 are rotatably supported on the main board 101 with shafts 164, 264 as fulcrums, and a portion thereof is located on the lower surface side of the presser plates 149, 249. ing. Further, the left rotation detecting member 163 is provided with an abutting portion 165 at its tip on the same side as the presser plate 149 when viewed from the shaft 164, and one end of a pressing rod 166 is attached. In addition, the shaft 26 is attached to the right rotation detection member 263.
A contact portion 265 is located on the opposite side of the presser plate 249 when viewed from 4.
is provided, and a guide portion 266 through which the pressing rod 166 is inserted is provided. When the holding plates 146, 249 rotate clockwise, the pressing protrusion 151a of the left holding plate 149 presses the left rotation detecting member 163.
is rotated to the right, and the pressing protrusion 251b of the right holding plate 249 presses the contact portion 265 of the right rotation detection member 263 to rotate this detection member 263 to the right. Conversely, when the presser plates 149, 249 rotate counterclockwise, the left presser plate 14
9 presses the left detection member 163 to rotate this member 163 to the right, and the press protrusion 251a of the right presser plate 249
Press the contact portion 265 of the right detection member 263 to rotate this member 263 to the right. In other words, when the presser plates 149, 249 rotate in any direction, a pressing force that rotates the rotation detection members 163, 263 to the right is generated. Here, it goes without saying that the rotational force of the presser plates 149, 249 is generated by the rotation of the reel shafts 107, 207.

On the other hand, on the front edge of the supply side detection member locking plate 114, left and right pressing pieces 167,
168 and another pressure piece 196 close to the right pressure piece 168. And the locking plate 114
is moving to the left, the left pressing piece 167
movement of the contact portion 165 to the right is prohibited, and when the locking plate 114 is moving to the right, the right pressing piece 168 prohibits movement of the contact portion 265 to the left.

On the lower surface of the switching gear 125, there are shown in FIGS.
A rotary claw 170 as shown in the figure is integrally formed. This has a point-symmetric shape with respect to the rotation axis,
Locking steps 171a and 171b are provided at two symmetrical locations.
It has the following. Further, a rotary cam 172 is integrally formed on the lower surface of the reverse drive gear 127. This has a spiral cam surface on the outer periphery, and a locking step 1 is provided between the maximum radius and the minimum radius.
73.

Further, in FIGS. 6 and 7, reference numeral 174 is a swing plate made of synthetic resin, which has an opening 175 into which the rotating cam 172 is inserted.
5 is provided with an engaging portion 176 on the right side edge thereof, and has a pressing protrusion 177 on the upper surface thereof, and is disposed to the right of the rotation detecting member 263 and the pressing rod 166.

Further, two parts are located near the switching gear 125.
Book locking levers 178, 179 are rotatably mounted. One of the locking levers 178 has a locking pawl at its tip engaged with one of the locking steps 171a and 171b on the outer periphery of the rotary pawl 170 (FIG. 6 shows one of the locking steps 171a and 171b). In this state, one of the rest portions 125a and 125b provided on the switching gear 125 is opposed to the gear 142 (see FIGS. 3, 4, and 9). (see figure). Further, one of the locking levers 178 is provided with a pressure receiving piece 180 and an engaging protrusion 181, and the pressure receiving piece 180 is connected to the rocking plate 1.
It is located in front of the pressing protrusion 177 of 74. The other locking lever 179 has one end facing the outer periphery of the rotary claw 170 from the side opposite to the one locking lever 178, and has an engaging protrusion 182 at the other end. A tension spring 183 is stretched between both the locking levers 178 and 179, and both levers 178 and
179 is urged in the direction of contact with the rotating claw 170. In addition, 184 in FIG. 6 is a manual operation force transmission lever, and this lever 184 has two pressing pieces 185, 1.
86 is provided in a bifurcated shape, and one of the pressing pieces 185 is brought into contact with the engagement protrusion 182 of the locking lever 180 to hold the locking lever 180 at a position spaced apart from the rotary claw 170.

Therefore, the left rotation detection member 163 is
66 and the right rotation detection member 263 directly applies a pressing force to the swing plate 174 from the left.

When the reel shafts 107 and 207 are rotating, the rotation detection member (163
or 263) acts on the swing plate 174, pressing the left side edge of the opening 175 against the outer periphery of the rotary cam 172. Note that the rotation detection member (163 or 263) on the tape supply side is prohibited from rotating in the right direction by the supply side detection member locking plate 114, so that the rotation detection member (163 or 263) on the tape supply side is prohibited from rotating in the right direction.
Or, the rotational force of 207) has no effect on the swing plate 174. Also, the swing plate 174 of the rotation detection member (163 or 263) on the tape winding side
The pressing force against the reverse friction mechanism (161 or 261) is generated by the transmission force of the reverse friction mechanism (161 or 261).
Compression coil spring 1 used in 61,261
Both 48 and 248 have small elastic modulus, so
The transmitted force is small, and therefore the pressing force acting on the rocking plate 174 is also very small.

By the way, when the rocking plate 174 is receiving a pressing force from the left in this way, the outer periphery of the rotating cam 172 comes into sliding contact with the left edge of the opening 175, and the rocking plate 17
4 swings from side to side as a result of this, and the locking stepped portion 173
However, the rotation of the reel shafts 107, 207 stops and the swing plate 17
When the pressing force acting on 4 disappears, the rocking plate 1
74 is held to the left by the maximum radius portion of the rotating cam 172. As a result, the 8th
As shown in the figure, the locking step portion 173 of the rotating cam 172 engages with the engaging portion 176 of the swing plate 174, and the rotating cam 17
2, the swing plate 174 moves in the direction of arrow A in the figure. For this reason, the pressing protrusion 177 provided on the rocking plate 174 is attached to the locking lever 178.
Press the pressure receiving piece 180 and rotate the locking lever 178 in the direction of arrow B in the figure. By this,
The locking lever 178 is disengaged from the locking step (171a or the locking step 171b) of the switching gear 125, and the locking state with respect to the switching gear 125 is released.

On the other hand, as shown in FIG.
b, and each time the switching gear 125 makes a half turn, the switching movable piece 187 is moved by the elastic member 188.
Switch by either a or 188b. The excessive amount of rotation of the rotation plate 117 is caused by the elastic member (188
a or 188b), and as a result, the restoring force of one of the elastic members (188a or 188b) is always applied to the switching gear 125 as a rotational force in the counterclockwise direction in the figure.

Therefore, as shown in FIG.
is the locking step of the rotating claw 170 (171a or 17
1b), the switching gear 125 rotates slightly counterclockwise due to the restoring force of the elastic member (188a or 188b), meshes with the constantly rotating gear 142, and is rotationally driven.

When the switching gear 125 rotates half a turn, the locking lever 178 engages with the locking step (171a or 171b) on the opposite side to stop the switching gear 125 again. Hole 1
19 causes the switching rotary plate 117 to perform a reverse operation. In addition, as the switch 124 is switched in accordance with the reversal operation of the switching rotation plate 117, the supply-side detection member locking plate 114 is moved to the left or right due to the engagement between the engagement hole 116 and the engagement pin 118. move towards

10 and 11 show the head mounting plate 10.
2 shows the relationship between the position of the supply-side detection member locking plate 114 and peripheral mechanisms when the supply-side detection member locking plate 114 is in the forward position (operating position). In this manner, when the head mounting plate 102 is in the forward position, the cam pin 112 of the pinch roller switching plate 111 is fitted into the recess 115a at the tip of the cam hole 115 provided in the locking plate 114.

In FIG. 10, the locking plate 114 is in the left position. At this time, the pressing piece 167 provided on the locking plate 114 presses the protrusion 122 of the left rotating plate 120 to the left, thereby separating the gear 121 from the gear 140. Further, as described above, the pressing piece 167 prohibits the left rotation detection member 163 from rotating in the right direction (see FIG. 6), and the rotation detection member 163 on the left and the swing plate 174 are prevented from rotating in the right direction. The connection is broken. Furthermore, the pinch roller switching plate 111 is tilted to the left, so that the left pinch roller 105 is pulled away from the capstan shaft 104 at the left end of the bar spring 113, and at the same time, the right pinch roller 105 is pulled away from the capstan shaft 104 at the right end of the bar spring 113. A roller 205 is pressed against the capstan shaft 204. Therefore, the rotational force of the motor 109 is transmitted to the right reel shaft 207, and the tape is transferred to the right capstan shaft 204 and the pinch roller 20.
5 and travels to the right in the figure, and is wound onto the right reel.

In contrast, in FIG. 11, the locking plate 114 is in the right position. The pressing piece 169 provided on the locking plate 114 presses the protrusion 222 of the right rotating plate 220 to the right, thereby separating the gear 221 from the gear 240. Further, as described above, the pressing piece 168 prohibits the rotation of the right rotation plate protruding member 263 in the right direction, and the rotation detection member 263 and the swing plate 17 on the right side are prevented from rotating in the right direction.
The connection with 4 has been severed. Furthermore, the pinch roller switching plate 211 tilts to the right, and the right end of the bar spring 113 moves the right pinch roller 205 to the capstan shaft 2.
04, and the left pinch roller 105 is pulled away from the capstan shaft 10 at the left end of the bar spring 113.
I'm pushing it to 4. Therefore, the rotational force of the motor 109 is transmitted to the left reel shaft 107, and the tape is held between the left capstan shaft 104 and the pinch roller 105, runs to the left in the figure, and is transferred to the left reel. It will be taken.

Figures 12 to 14 show the head mounting plate 102.
This figure shows a mechanism for moving the motor from the rear limit position (stop position) to the forward position (operating position).

A drive gear 189 is located near the gear 138.
It is attached to the back side of the main board 101. This gear 189 has a resting part 190 with a part of the tooth profile cut out.
A spring receiving protrusion 191 is provided on the upper surface, and a spiral rotating cam 192 and a stop locking portion 19 are provided on the lower surface.
It has 3. Further, a stopper wall 194 is provided protruding from the peripheral edge of the lower surface of the gear 189. Further, an operation locking portion 195 is provided protruding from a position near the stop locking portion 193 .

On the other hand, the movable iron core 110a of the magnetic plunger 110 is always urged in the direction of extension by the coil spring 110b, and when the solenoid is energized by insertion of the cassette, it is pulled into the solenoid.

In addition, 196 in the figure is a locking lever, and this lever 1
One end of the 96 is a cam engaging portion 196a, and the other end is a plunger engaging portion 196b. The plunger engaging portion 196b engages with the tip of the movable core 110a of the magnetic plunger 110, and the cam engaging portion 196a is arranged along the lower surface of the rotary cam 192. Furthermore, 197 in the figure is a leaf spring (a rod spring is also acceptable), which is connected to the spring receiving protrusion 19.
1 is brought into pressure contact with the free end to apply rotational force to the drive gear 189 in the counterclockwise direction in the figure.

Furthermore, 198 in the figure is a cam lever, which is rotatably supported on the back surface of the main board 101, and has one end attached to it.
It has a cam follower 198a that comes into sliding contact with the cam surface of the rotating cam 192. A bar spring 199 having a large elastic modulus is attached to the cam lever 198, and the tip of the bar spring 199 is engaged with a portion of the head mounting plate 102. In addition,
In the figure, reference numeral 200 is a tension spring for returning the head mounting plate 102 from the operating position to the stop position.
is configured to be pressed against the cam surface of the rotary cam 192.

Therefore, when stopped, the cam engaging portion 196a of the locking lever 196 engages with the stopping portion 193 as shown in FIG. 12, and the resting portion 190 is opposed to the gear 138. Further, the elastic force of the leaf spring 197 acts on the spring receiving protrusion 191, and a rotational force is applied to the gear 189 in the counterclockwise direction in the figure. The cam follower 198a is located at the smallest radius of the rotating cam 192, and therefore the head mounting plate 10
2 is held in a retracted position (stop position) by a tension spring 200 (see FIG. 3).

When the tape cassette is inserted in this state, the solenoid of the magnetic plunger 110 is energized, the locking lever 196 is rotated by the operation of the movable core 110a, and the cam engaging portion 196a is released from the locking portion 193 when stopped. Then, as shown in FIG. 13, the drive gear 189 is slightly rotated by the leaf spring 197 and meshes with the gear 138.

Therefore, the rotation of the gear 138, that is, the rotation of the motor 109, is now transmitted to the drive gear 189, and the drive gear 189 rotates approximately one rotation in the counterclockwise direction. During this time, the cam follower 198 moves to the maximum radius of the rotary cam 192, and the cam follower 198 rotates greatly, moving the head mounting plate 102 to the movable position against the tension spring 200 (FIG. 14). At this time, the cam engaging portion 196a engages with the locking portion 195 during operation to stop the drive gear 189, but the resting portion 190 again faces the gear 138 and the leaf spring 197 engages with the spring receiving protrusion 191. The drive gear 189 is held in a state where it is in pressure contact and a counterclockwise rotational force is applied to the drive gear 189.

Further, when the magnetic plunger 110 is brought into a stopped state, the power supply to the magnetic plunger 110 may be stopped. Simultaneously with the energization being stopped, the movable iron core 110a returns to the extension direction, the cam engaging portion 196a of the locking lever 196 is disengaged from the locking portion 195 during operation, the drive gear 189 is slightly rotated by the leaf spring 197, and the cam follower 198a is rotated slightly by the leaf spring 197. Since the head panel 102 falls to the minimum radius portion of the rotating cam 192, the head panel 102 is returned to the stopped position by the return spring 200.

A mechanism (not shown) is provided to rotate the rotating plates 120, 220 in conjunction with the backward movement of the head mounting plate 102, and to separate the left and right gears 121, 221 from the gears 140, 240. At the same time as the head mounting plate 102 returns, the rotational force transmission path from the motor 109 to both the reel shafts 107, 207 is cut off.

The configuration of the above embodiment corresponds to the schematic diagram shown in FIG. 2 as follows.

That is, it goes without saying that the reel shafts 107, 207 and the rotation detecting members 163, 263 respectively correspond to the reel shafts a1, a2 and the rotation detecting members b1, b2 in FIG. The supply-side detection member locking portion 114 corresponds to the supply-side detection member locking mechanism e in FIG. 2, corresponding to the friction mechanisms c1 and c2 in FIG. Also, a so-called auto-reverse mechanism including the swing plate 174, the switching gear 125, the reverse driving gear 127, the locking lever 178, and the supply side detection member locking plate 114 corresponds to the operating section in FIG.

In the above embodiment, the tape running direction can also be manually switched by moving the manual operating force transmission lever 184 shown in FIG. 8 to the left either directly or via some mechanism. That is, when the lever 184 is moved to the left,
First, the left locking lever 179 comes into contact with the peak of the rotary pawl 170, and then the pressing piece 186 touches the locking lever 1.
78 to the left to move the locking lever 178 to the locking stepped portion (171a) of the rotating claw 170.
or 171b), and then the above-described operations are performed. The left locking lever 179 prevents the rotary claw 172 from rotating more than half a turn even if the manual operating force continues to act for a long time, thereby preventing malfunctions such as continuous switching.

〔Effect of the invention〕

As described above based on the embodiments, according to the tape end detection device of the present invention, even if the reel shaft on the tape supply side stops for some reason, it will continue to operate as long as the reel shaft on the tape winding side does not stop. This does not have any influence on the parts, and it is possible to reliably prevent malfunctions from occurring.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing the prior art, FIG. 2 is a schematic diagram showing an outline of the present invention, and FIGS. 3 to 14
The figures show one embodiment of the present invention, in which Fig. 3 is a schematic plan view showing the mechanical part of the tape recorder, Fig. 4 is a plan view showing the rotation transmission path, and Fig. 5 is a longitudinal sectional view of the reel shaft. , Fig. 6 is a plan view showing the rotation detection member and its related mechanism, Fig. 7 is a vertical cross-sectional view of the area surrounding the switching gear, Fig. 8 is a plan view of the area surrounding the swing plate, and Fig. 9 is a plan view of the switching gear and its relationship. FIGS. 10 and 11 are plan views showing the supply side detection member locking plate and its related mechanisms, and FIGS. 12 to 14 are plan views showing the mechanism for driving the head mounting plate. be. 107, 207... Reel shaft, 114... Supply side detection member locking portion, 125... Switching gear, 127
... Reverse drive gear, 161,261 ... Reverse friction mechanism, 163,263 ...
Rotation detection member, 174... rocking plate.

Claims (1)

[Claims] 1 A pair of capstans 104 and 204 rotationally driven by a motor 109, and each capstan 1
Pinch roller 105,2 corresponding to 04,204
05, and the motor 109 via a rotation transmission mechanism.
A pair of reel shafts 107, 207 that receive the rotational force of
and a pair of rotation detecting members 163, 263 provided on each of the pair of reel shafts 107, 207 and biased in one direction by transmitting the rotational force of each reel shaft 107, 207 via a friction mechanism;
A pair of reel shafts 10 from the motor 109 in the rotation transmission mechanism are alternately selected from two positions.
a locking plate 114 that selectively blocks one of the rotation transmission paths leading to the capstan 7 and 207, prohibits movement of the rotation detection member on the same side, and separates the pinch roller from the capstan on the same side; This locking plate 114 is biased by the rotation detection member whose movement is not prohibited, and when the biasing force of the rotation detection member disappears, a reverse mechanism switches the position of the locking plate in response to the rotational force of the motor. A tape end detection device for a tape recorder, comprising: