JPS6355142B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic recording and reproducing apparatus in which a magnetic tape is pulled out from a tape cassette and mounted on a magnetic head drum, and thereafter various modes are switched to perform desired recording and reproducing operations. Regarding the drive switching device, in particular, a single drive source is used to drive the tape mounting means for mounting the magnetic tape on the magnetic head drum and the operation mode switching means for switching the mechanism mode such as recording/playback or fast forward/rewind. The present invention provides a drive switching device that can operate in coordination with each other by switching between the two, thereby reducing the size and weight of the device, reducing consumption, and ensuring reliable operation of the mounting mechanism.

In the tape mounting means of a magnetic recording and reproducing apparatus that generally uses a tape cassette, or the operation mode switching means for recording and reproducing, one method is to use a dedicated motor for each of the tape mounting means and the operation mode switching means. Another method is to use a dedicated motor for the former and a large number of electromagnets for the latter, and another method is to use a dedicated motor for the former to perform each operation. A type has been devised in which the tape mounting means is operated and a cam portion is provided on the tape mounting means to switch between various modes. In these conventional methods, the tape mounting means and the operation mode switching means each require a dedicated motor or a drive source such as an electromagnet, and therefore it is not possible to reduce the size and weight of the apparatus. Furthermore, since multiple drive sources are required, especially in portable models, low power consumption cannot be expected, resulting in drawbacks in terms of long-term photography.

Furthermore, in the case of a structure that uses a cam, the structure mechanism is very complex and has a large number of parts, and there are problems with assembly work, assembly accuracy, and durability. It could not be said to be sufficient as it lacked accuracy.

The present invention can accurately and cooperatively switch two mechanical means by switching their loads with one drive source,
It is an object of the present invention to provide a drive switching device that achieves reduction in size and weight of the device, improvement in assembly workability, etc. of the device, and allows stable and accurate operation of the device mechanism.

An embodiment of the drive switching device according to the present invention will be described below with reference to the drawings. In FIG. 1, 1 is a device board, 2 is a motor pulley for driving a capstan, and is connected to a capstan 5 fixed to the flywheel 4 via a belt 3 and a flywheel 4. In FIG. 6 is a pinch roller that presses the magnetic tape 21 against the capstan 5; 7 is an arm for the pinch roller rotatably connected to a shaft erected on the substrate 1; this arm 7 is connected to an operation mode switching means 14 (described later); (not shown), and the pinch roller 6 is connected to the capstan 5 only in the recording/playback mode.
It is configured to press against the Reference numeral 8 denotes a running post, and the magnetic tape 21 is wound around the running post 8 only when the pinch roller 6 presses the capstan 5. 9 is a cassette, and inside the cassette 9 are a take-up reel 10 and a supply reel 1.
1 and a plurality of posts 32 and 33 are provided. Reference numeral 12 denotes a center pulley for driving a reel, which is provided at a position approximately midway between a supply reel stand 35 and a take-up reel stand 36, which will be described later. Due to the movement of , the drive idler 13 comes into contact with the center pulley 12 , and the center pulley 12
For example, during rewinding, the center pulley 12 rotates in the counterclockwise direction of arrow A, so the idler 13 is deflected counterclockwise by the frictional force and moves to the position 13'. During winding, the center pulley 12 rotates in the clockwise direction of arrow B, so the idler 13 is deflected clockwise and moves to the 13'' position, transferring the rotational force of the center pulley 12 to each supply reel. 11
and is configured to be transmitted to the take-up reel 10. Reference numerals 15 and 16 denote a main ring and a sub-ring constituting the tape mounting means 37, each of which has a toothed portion formed on its outer periphery to be coupled to a first output portion 18 of a planetary gear unit portion 38, which will be described later. . 17
A plurality of restriction rings are provided to support the main ring 15 and the sub-ring 16. Reference numeral 19 denotes a second output section of the planetary gear unit 38, and this second output section 19 is engaged with the tooth forming section of the operation mode switching means 14. 20 is a tension servo lever that rotates the magnetic tape 2 in the recording/reproducing mode.
1 and performs back tension of the magnetic tape 21.

22 is a magnetic head drum incorporating at least one magnetic head 39, 23 is an audio control head, 24 is an audio erase head, and 25 is a full erase head. A tape drawer post 26 is led by the main ring 15, and is located in the recess 34 of the cassette 9 before operation, and moves to the position 26' when the magnetic tape 21 is completely loaded.

Reference numerals 27, 28, and 29 denote a plurality of correction posts provided on the sub-ring 16, which are provided as a unit on the correction table 54, which will be described later. 27', 2 when the magnetic tape 21 is fully loaded.
Move to the positions shown at 8' and 29'. Although not shown in the drawings, the correction table 54 is configured so that its connection position with respect to the sub-ring 16 changes just before the movement ends, and the advancing side part changes slightly so that it opens.
This is effective in reducing the size of the device or reducing the amount of the recessed portion 34 of the cassette 9, thereby reducing the size of the cassette. Reference numerals 30 and 31 are regulating posts that regulate the entrance and exit positions of the magnetic tape 21 on the magnetic head drum 22.

FIG. 2 illustrates the planetary gear unit section 38. 40 is a worm directly connected to a motor (not shown) which is a drive source that rotates in forward and reverse directions; 41 is a worm wheel gear that meshes with the worm 40; They are rotatably connected, and the engagement described above achieves prevention of reverse rotation. Further, a tooth portion 44 is provided on a part of the worm wheel gear 41, and constitutes a sun gear 52. A planetary gear 45 is rotatably connected to a shaft 46 provided on a part of an arm gear 47 which is also rotatably connected to the shaft 42, and meshes with the teeth 44 of the sun gear 52 on one side and on the other side. It meshes with internal teeth 53 of an internal gear 48 rotatably connected to a part of the sun gear 52. 49 is a shaft supporting the first output section 18 of the planetary gear unit section 38, and the first output section 18 is connected to the arm gear 47 on the other hand.
while meshing with the main ring 15 on the other hand,
It meshes with the sub ring 16 with a diameter difference. As is clear from FIG. 1, the difference in diameter between the main ring 15 and the sub-ring 16 is provided between the tape pull-out post 26 and the correction posts 27, 28, 29.
This is because the rotational movement amounts of the groups are different, and for this reason, a diameter difference is given to the main ring 15 and the sub-ring 16 to form a differential gear configuration. 50 is a planetary gear unit part 38
The second output section 19 is a shaft that supports the second output section 19 of the internal gear 4.
It meshes with the external teeth 51 of No. 8, and also meshes with the operation mode switching means 14 on the other hand. The planetary gear unit section 38 is constituted by the gear section described above.

FIGS. 3 and 4 are detailed views of the tape drawer post 26 and correction posts 27, 28, and 29 described above. Reference numeral 54 denotes a correction table, on the top of which correction posts 27, 28, and 29 stand up at respective correction angles, and on the other hand, a biasing plate spring 55 is coupled to the bottom surface of the table, and holds the sub-ring 16 mentioned above. ing. As described above, the correction table 54 can move somewhat, but in order to absorb the looseness of the movement, the sub ring 16 and the correction table 54 are coupled with a spring (not shown). 56 is a main boat on which the tape drawer post 26 is placed and fixed, and the groove 62 of the sub ring 16
A bearing portion 61 thereof is provided so as to penetrate therethrough. A grip hand 57 is integrally fixed to the main boat 56 and moves along a guide plate 64 which is held in a spiral shape with respect to the plane of the board 1 by a plurality of support plates 63 fixed to the board 1. , is connected by a connecting member 58 via a shaft 60 to a connecting member 59 fixed to the main ring 15, and the main boat 56 is pulled by the connecting member 58 connected to the main ring 15 when rotating. , the magnetic tape 21 is moved along a guide plate 64 provided in a spiral shape to mount the magnetic tape 21 at a predetermined position.

Next, the magnetic tape drive mechanism shown in FIGS. 5 to 7 will be explained. In FIG. 5, the operation mode switching means 14 is meshed with the second output section 19 of the planetary gear unit section 38 through teeth provided on a part thereof, and is held by a shaft 65. Further, a part of the operation mode switching means 14 is connected to the cassette storage section 67.
(The whole is not shown, only the hooked part is shown.)
A pin 69 fixed to a locking means 66 for locking the
The first elastic members 68 are connected to each other so as to be attracted to each other by a first elastic member 68. First elastic member 68
The initial tension is the first tension of the planetary gear unit portion 38.
It is set to a value larger than the moving operation load of the tape mounting means 37 applied to the output section 18 of. 70
is a hook portion provided on a part of the locking means 66, and is configured to lock the cassette storage portion 67 when the locking means 66 rotates in the direction of arrow C. Reference numeral 71 represents a stopper portion that restricts rotation of the locking means 66, and reference numeral 72 represents a shaft that holds the locking means 66. A second elastic member 73 is engaged with a portion of the locking means 66 on one side and coupled to the substrate 1 on the other side, and has the same initial tension as the first elastic member 68. Reference numeral 74 denotes an arm provided on a part of the locking means 66, which is configured to push a switch (not shown) when the locking means 66 rotates in the direction of arrow C. This locking means 66 is configured to operate integrally with the operation mode switching means 14 until a part thereof contacts the stopper portion 71, and after it contacts the stopper portion 71, only the operation mode switching means 14 operates. ing. A cam portion 75 is formed in a part of the operation mode switching means 14, and a contact ring 78 fixed to a direction changing lever 76 that rotates around a shaft 77 comes into contact with the cam portion 75.
The operation mode switching means 14 is configured to rotate in the direction of arrow E in response to movement in the direction of arrow D. Reference numeral 79 denotes a slide plate, a part of which engages with the direction changing lever 76 to operate integrally, and is configured to move in the direction of the arrow F in response to rotation of the direction changing lever 76 in the direction of the arrow E. ing. Although not shown, the movement of this slide plate 79 releases the reel stand brake means. 80 is a shaft that holds the slide plate 79, and 83 is a return spring that returns the slide plate 79 from the operating state and brings the contact ring 78 of the direction change lever 76 into contact with the cam portion 75 of the operation mode switching means 14. It also has the effect of Reference numeral 82 designates an idler arm having a stepped groove 87 in a part thereof, and a shaft 81 having a slide groove 84 is fixed to the other side of the idler arm 82 as shown in FIG.
4 engages with the groove 86 of the slide plate 79 and is movable. Further, a shaft 85 is fixed to the center of the stepped groove 87 of the idler arm 82, and the drive idler 13 is rotatably fitted onto the shaft 85. Further, on the side of the center pulley 12 of the idler arm 82, as shown in detail in FIGS. 6 and 7, there is a recessed portion having a radius substantially the same as or larger than that of the elastic body ring 89 integrally connected to the center pulley 12. 90 is formed. This recess 90 is formed when the drive idler 13 moves toward the center pulley 12 during operation.
3 contacts the elastic body ring 89 before contacting the center pulley 12, and if the center pulley 12 is rotating to the left or right, the drive idler 13 is deflected in the direction of rotation, and the center pulley 12 is stopped. If so, the elastic body ring 89 and the recess 90 are engaged with each other so that the drive idler 13 is held at the neutral position without being deflected to either the left or right. 88 is a balance plate, one of which is engaged with the stepped groove 87 of the idler arm 82, and the other is engaged with the arm 92 of the slide plate 79 and the spring 91.
are engaged through. Furthermore, the above-mentioned idler arm 82, center pulley 12, and spring 91 are arranged in a straight line, so that the drive idler 1 is always connected during operation.
3 is configured to press against the center pulley 12. 93 in FIG. 1 is the tape mounting means 37.
This is a stop member that regulates the starting and ending ends of.

Further, reference numeral 94 shown in FIG. 5 is a locking lever constituting the regulating means 100. An engaging pin 95 is provided on one side of the locking lever 94, and is biased by a spring 99 to switch the operation mode switching means 14. It engages with the cam portion 101. Moreover, the tape mounting means 3 is mounted on the other side.
A toothed portion 96 is formed to engage with the secondary ring 16 (or the main ring 15) of No. 7, and the locking lever 94 is rotated in the direction of the arrow by movement of the operation mode switching means 14 in the D' and D'' directions. 97 is one hook part of a spring 99 provided on the locking lever 94, and 98 is a spring provided on the board 1. The other hook part 99 and 102 are the locking levers 9.
4 and a spring 99 are rotatably coupled to each other.

Next, the operating state of the above configuration will be explained in the following order. 1, 5, and 9 show the locked state of the cassette storage section 67, followed by FIG. 9 showing the loaded state of the magnetic tape 21, and then FIG. 10 showing the stopped state. Fig. 11 shows the recording/reproducing device, and Fig. 12 shows the winding and fast forwarding states.
Next, the cassette removal state will be explained with reference to FIGS. 13 and 5. First, the locking of the cassette storage section 67 will be explained with reference to FIGS. 1, 5, and 9.
When the set 9 is installed in the cassette storage section 67 before operation of the device, when some operation, for example, a recording/reproduction switch is turned on, the drive source of the planetary gear unit 38 rotates in the forward direction, and the drive source directly connected to the drive source rotates in the forward direction. The worm 40 rotates. One side of the rotation is the sun gear 52, the planet gear 45, and the arm gear 47.
The other signal is transmitted to the first output section 18 via the sun gear 52, the planetary gear 45, and the internal gear 48 to the second output section 19. At this time, the first output section 18 of the planetary gear unit section 38
The load of the tape mounting means 37 is applied to the second output part 19, and the second
Although the restoring force of the elastic member 73 is applied, the load on the tape mounting means 37 is relatively larger, and the driving force of the planetary gear unit 38 is transmitted to the second output section 19, and the operation mode is switched. The means 14 and the locking means 66 are moved together in the directions of arrows C and D', respectively. Therefore, as shown in FIG.
The direction changing lever 76 is rotated in the direction of the arrow E by the cam portion 75 of No. 4, and the slide plate 79 engaged with the direction changing lever 76 is rotated by the spring 83 in the direction of the arrow F.
, and release the reel stand brake means. At this time, the operation mode switching means 1
Due to the movement of the cam portion 101 of No. 4, the locking lever 94
is the sub ring 1 of the tape mounting means 37 shown in FIG.
As shown in FIG. 9, the locking state of the tape mounting means 37 is released from the locking state with 6, and the rotating operation of the tape mounting means 37 changes from the locked state to the rotatable state. Therefore, after the cassette storage section 67 is locked, the tape mounting means 37 becomes operable, so that damage to the tape during operation of the apparatus can be prevented. Further, when the direction changing lever 76 is rotated, the drive idler 13 is moved by the spring 91 so that the recess 90 of the idler arm 82 is fixed to the center pulley 12 because the center pulley 12 is not rotating. The reel stands 35 and 36 are held in the neutral position, and the reel stands 35 and 36 become free. As the movement continues, a part of the locking means 66 becomes attached to the stopper part 71.
, the restoring force of the second elastic member 73 ceases to operate, and the load of the first elastic member 68 acts on the second output section 19 of the planetary gear unit section 38 mentioned above. Since this load is larger than the operating load of the tape mounting means 37 applied to the first output section 18, the driving force of the planetary gear unit section 38 is
The signal is switched and transmitted from the output section 19 of the first output section 18 to the first output section 18 .

Next, the operation from the tape loaded state to the stopped state will be explained with reference to FIGS. 1, 9, and 10. When the driving force of the planetary gear unit 38 is switched from the second output section 19 to the first output section 18, the main ring 15 and the sub-ring 15 constituting the tape mounting means 37 connected to the first output section 18 ring 16
The magnetic tape 21 is rotated in the direction of arrow G in FIG.
3. The magnetic tape 21 is sequentially mounted on the audio erase head 24, the full erase head 25, and the posts 30 and 31. At this time, since the main ring 15 and the sub ring 16 have a differential gear configuration, the main ring 15 rotates faster than the sub ring 16. Furthermore, the brake means on the reel stands 35 and 36 are released, and the drive idler 13 is not deflected and is held at a neutral position, so that the magnetic tape 21 is smoothly and easily drawn out from the cassette 9. Then, the rotation progresses further and the tape drawer post 2
6 and the correction posts 27, 28, 29 are moved to predetermined positions, and their rotation is stopped by the stop member 93.
, the operating load on the first output section 18 of the planetary gear unit section 38 increases rapidly and becomes greater than the load on the first elastic member 68 . When the magnitude of the load is reversed, the driving force of the planetary gear unit 38 is again switched and transmitted from the first output section 18 to the second output section 19.
Only the operation mode switching means 14 coupled to the second output section 19 is moved against the first elastic member 68 to reach the stop state shown in FIG. 10, and is stopped by a position detection switch (not shown). . At this time, the drive idler 13 is released from the neutral position shown in FIG. 9 and returns to its original state, and the braking means also acts on the reel stands 35 and 36.

Next, the recording and reproducing state will be explained with reference to FIG.
If you turn on either the recording or playback (mechanism operation is the same) switch from the stop state in Figure 10,
The driving force of the planetary gear unit section 38 is continuously transmitted to the second output section 19 in the forward direction for the reason described above, and the operation mode switching means 14 is further moved in the direction of the arrow D' to reach the state shown in FIG. The position detection switch operates and stops. At this time, slide plate 7
Since the direction changing lever 76 is rotated in the direction of the arrow E, the direction change lever 9 moves in the direction of the arrow F, and the drive idler 13
also comes into contact with the center pulley 12. At this time, since the center pulley 12 is rotating in the direction of arrow B, the elastic body ring 89 of the center pulley 12 creates a recess 90 in the idler arm 82 and deflects it toward the take-up reel stand 36. However, the drive idler 13 is biased by a spring 91 and wedges between the center pulley 12 and the take-up reel stand 36, so that the rotation of the center pulley 12 can be transmitted to the take-up reel stand 36. At this time, slide plate 79
, the brake means is released, the pinch roller 6 is pressed against the capstan 5 by the operation mode switching means 14, and the tension servo lever 20 is also operated.
is slowly wound onto a take-up reel, and recording or reproducing operations are performed. When changing from the recording or playback state to the stop state, when the stop switch is turned on, the drive source of the planetary gear unit 38 rotates in the opposite direction, and the output is transferred to the first output section 18 because the first elastic member 68 acts as a restoring force. The load on the second output section 19 is lighter, and the driving force is lower than that of the second output section 19.
is transmitted as a reverse operation to the output section 19 of the second
Operation mode switching means 14 coupled to the output section 19 of
is moved in the direction of arrow D'' and stops in the state shown in FIG. 10 in which the position detection switch is activated, and the drive idler 13, pinch roller 6, and tension servo lever 20 also return to their original states.

Next, rewinding and fast forwarding will be explained. Since these two mechanical operations are the same, and only the direction of rotation of the center pulley 12 is different, the unwinding state will be explained with reference to FIG. 12. First, the rewind switch is turned on, and the drive source of the planetary gear unit 38 rotates in reverse, and its driving force is transferred to the second output for the same reason as when moving from the recording/reproducing state to the stop state. 19, the operation mode switching means 14 coupled to the second output section 19 is moved in the direction of arrow D'' and stopped in the state shown in FIG. is rotated in the direction of arrow E, the slide plate 79 also moves in the direction of arrow F, and the drive idler 13 also comes into contact with the center pulley 12.At this time, the center pulley 12 rotates in the direction of arrow A. , an idler arm 82 in contact with an elastic body ring 89 provided on the center pulley 12
The recess 90 of the idler arm 82 is oriented in the direction of arrow A, and the drive idler 13 provided on the idler arm 82 is biased by a spring 91 and bites between the center pulley 12 and the supply reel stand 35, so that the center pulley 12
The rotation of the magnetic tape 21 can be transmitted to the supply reel stand 35 to rewind the magnetic tape 21. To change from this rewinding operation to the stop state, turn on the stop switch and the planetary gear unit 38
The driving source rotates in the forward direction, and its driving force is also transmitted to the second output section 19 for the above-mentioned reason, and the operation mode switching means 14 coupled to the second output section 19 is moved in the direction of arrow D'. Then, the position detection switch is operated, and the state shown in FIG. 10 is restored and stopped, and the drive idler 13 is also restored.

Next, the cassette removal process will be explained with reference to FIGS. 13 and 5. When the cassette eject switch is turned ON from the stop state shown in FIG.
is applied as a restoring force, and the load on the second output section 19 is smaller than that on the first output section 18.
The operation mode switching means 14 coupled to the second output part 19 moves in the direction of arrow D'', and the pin 69 fixed to the locking means 66 moves in the direction of arrow D''.
as shown in Fig. 13. When abutting, the return force of the first elastic member 68 disappears, and the load of the second elastic member 73 acts on the second output section 19 of the planetary gear unit section 38, so that the second output section 19 of the planetary gear unit section 38 The load on the second output section 19 is greater than the load on the first output section 18 . Therefore, the driving force of the planetary gear unit 38 is switched to the first output section 18, and the tape mounting means 37 connected to the first output section 18 is switched to the first output section 18.
Move it in the direction of arrow H in the figure. At the same time, the movement of the cam portion 75 of the operation mode switching means 14 causes the direction conversion lever 76 and the slide plate 79 to move in the directions of arrows E and F, respectively. Therefore, the drive idler 13 also comes into contact with the center pulley 12 as it moves towards it. At this time, the center pulley 12 is pointing at arrow A.
Since the idler arm 82 is rotating in the direction shown in FIG.
is biased by a spring 91 and bites between the center pulley 12 and the supply reel stand 35, transmits the rotation of the center pulley 12 to the supply reel stand 35, and causes the tape mounting means 37 to return in the direction of arrow H. The magnetic tape 21 is wound up to absorb the slack of the magnetic tape 21 that occurs.

As these operations proceed further, the magnetic tape 21 is completely wound up in the cassette 9, and the magnetic tape 21 is completely wound onto the tape mounting means 3.
7 is prevented from moving by the stop member 93, the load applied to the first output section 18 of the planetary gear unit 38 increases rapidly and becomes larger than the load on the second elastic member 73. . Then, the driving force of the planetary gear unit 38 is transferred to the first output section 1.
8 to the second output section 19, and the operation mode switching means 14 changes from the state shown in FIG. 13 to the state shown in FIG.
and the locking means 66 are integrally connected to the second elastic member 7.
3, and stopped at the position by the position detection switch. When moving from the state shown in FIG. 13 to the state shown in FIG. 5, the cam portion 7 of the operation mode switching means 14
5, the drive idler 13 returns to its original position, and at the same time, the cassette storage section 67 is unlocked, and the cassette 9
can be taken out. Further, due to the rotation of the locking means 66, the locking lever 94 of the regulating means 100 rotates as shown in FIGS. The movement of the mounting means 37 is restricted.

As described above, the present invention has the following effects.

(i) Since the tape mounting means, the operation mode switching means, and the lock of the cassette storage section can be operated in coordination with one drive source, it is effective in reducing the size and weight of the apparatus.

(ii) Regarding the operation in item (i), when the operation starts, the cassette storage section is locked, and then other mechanisms such as the tape loading means operate, and when the cassette is removed, the drive mechanism etc. Since the lock of the cassette storage section is released after the magnetic tape is rewound and the magnetic tape is rewound, the accuracy of the operation of the apparatus is improved and damage to the tape can be prevented when the cassette is inserted or removed.

(iii) Regarding the operation of item (ii), after the cassette storage section is locked by the restricting means, the tape loading means is released to allow movement, so that the effect of item (ii) can be further improved.

(iv) Since it can be performed using a single driving source, it is effective in reducing power consumption and increasing the recording time, especially in portable models.

(v) Regarding item (ii), each operation can be adjusted as a single unit, and there is no need to adjust the timing of connections between mechanisms, making assembly and adjustment of parts very easy.

It has many practical effects such as.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the overall configuration of an embodiment of the present invention;
The figure is an explanatory diagram of the structure of the planetary gear unit, Figures 3~
Fig. 4 is a detailed partial view of the tape mounting means, Fig. 5 is a configuration diagram of the tape drive unit before the device operates, Figs. 6 to 8 are partial explanatory views thereof, and Fig. 9 is the tape mounting state. 10 is an explanatory diagram of the drive unit in the stop state, and FIG. 11 is an explanatory diagram of the drive unit in the stop state.
Explanatory diagram of the drive unit in recording and playback mode, 1st
FIG. 2 is an explanatory diagram of the driving section showing the winding state in the winding fast-forward mode, and FIG. 13 is an explanatory diagram of the driving section during the cassette unloading process. 14... Operation mode switching means, 18... First output section, 19... Second output section, 26... Tape drawer post (main post), 27, 28, 29...
...Correction post (sub-post), 38...Planetary gear unit section, 66...Lock means, 67...Cassette storage section, 68...First elastic member, 70...Stopper section, 73...Second Elastic member, 93...
Stopping member, 100...Regulating means.

Claims (1)

[Claims] 1 A planetary gear unit part coupled to a drive source through an inversion prevention means at an input part and having a first and second output part, and a third part of the planetary gear unit part on which at least a magnetic tape drawer post is placed. a tape mounting means coupled to the second output section of the planetary gear unit; and an operation mode switching means coupled to the second output section of the planetary gear unit; a regulating means that engages with the racking means so that only one of them operates; and a tape mounting means connected to the first output part of the planetary gear unit, which is larger than the load during the mounting operation process. a first elastic member having an initial tension, a locking means for the cassette storage section coupled to the operation mode switching means so as to be attracted to each other by the first elastic member, and a locking means for locking the cassette storage section to the locking means It consists of a second elastic member coupled to bias it, a start/end stop member that restricts the amount of movement of the tape mounting means, and a stopper portion of the locking means, and when the magnetic tape is mounted, the locking means locks the tape into the cassette. 1. A drive switching device for a magnetic recording/reproducing apparatus, characterized in that said regulating means is operated so that a tape loading means is operated after the tape is locked.