JPH0481052B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention provides a main side gear capable of multiple rotations, and a main side gear that rotates intermittently and within a range of less than one rotation in accordance with the rotation of the main side gear. The present invention relates to a drive device having a gear and a driven gear.

[Background of the invention]

Various types of drive devices have been proposed that have a plurality of gears and perform a plurality of drive operations by causing a time lag in the rotation of each gear.

For example, in the case of a magnetic recording/reproducing device such as a VTR, a pin of a cassette mounting lever is engaged with a surface cam on the top surface, and a pin of an engagement/disengagement switching means having a lever and an elastic body is engaged with a surface cam on the bottom surface. a first gear formed by a pin of a pinch roller moving lever being engaged with a surface cam on the top surface, and a pin of a tape pull-out lever being engaged with a surface cam of the bottom surface; , the drive source transmits the driving force only to the first gear so that it can rotate multiple times, and when the first gear rotates a predetermined amount, the cassette mounting lever operates, The second gear meshes with the first gear and rotates in a driven manner in different phases, thereby operating the pinch roller moving lever and the tape pulling lever, and furthermore, these first and second gears operate. A drive device has been proposed in which the engagement and disengagement between the two motors is performed by the engagement/disengagement switching means, thereby allowing one motor to perform a plurality of temporally non-identical drive operations.

Hereinafter, a conventional example of a drive device having such a gear will be described in more detail.

2 and 3 are explanatory diagrams showing the main parts of a conventional example of this type of drive device, and FIG. 2 is a plan view;
FIG. 3 is a side view. Note that this conventional example
An example of application to a VTR drive section is shown. In these figures, 1 is the motor, 2 is this motor 1
3 is a belt that transmits the rotational force of the motor 1 to the pulley 2; 4 is a worm that rotates integrally with the pulley 2; 5 is a worm wheel that engages with the worm 4; 6 is the worm wheel 5. It is a gear formed at the bottom of the .

The above-mentioned worm wheel 5 and gear 6 are integrated to form a main gear, and as shown in FIG. 3, the worm wheel 5 and the gear 6 are mounted on a first shaft 8 fixed to the chassis 7 for multiple rotations, for example, two rotations. There is. Further, the worm wheel 5 has a surface cam 10 forming a concave portion on its surface 9 as shown in FIG.
0 is an approximately two-turn winding having a portion 13 that gradually approaches the center from position 11 to position 12, and a portion 14 that is continuous with this portion 13 at position 12 and is approximately equal in distance from the center. It is formed in a spiral shape. In addition, the gear 6 mentioned above
The surface 18 located below FIG. 3 of FIG.
As shown in ~c, another surface cam 19 is formed, and this surface cam 19 is provided at a position far from the center, and has a portion 20 that is approximately equal in distance from the center.
, a portion 21 provided at a position close to the center and having approximately the same distance from the center, and these portions 20
and a portion 22 connecting the portions 21 and 21, and is formed in an approximately two-turn spiral shape. A gear portion 23 and a non-gear portion 24 corresponding to the addendum circle are formed on the circumferential side of the gear 6.

Reference numeral 15 shown in FIG. 2 is a cassette mounting lever, which is rotatably mounted on a shaft 16 fixed to the chassis 7 and has a pin 17 that engages with the surface cam 10 of the worm wheel 5 described above. Reference numeral 25 denotes a subordinate gear that can be engaged with and disengaged from the gear 6, and is rotatably mounted on a second shaft 26 fixed to the chassis 7 within a range of less than one rotation. A surface cam (not shown) is formed on the upper and lower surfaces of the subordinate gear 25, and on the circumferential side thereof, a gear portion 27 and a non-gear portion corresponding to the gear circle are formed as shown in FIGS. 28
is formed. Reference numeral 29 denotes a pinch roller moving lever, which has a pin 30 that engages with a surface cam (not shown) formed on the upper surface of the follower gear 25, and is rotatably mounted on a shaft 31 fixed to the chassis 7. There is. Reference numeral 32 denotes a tape drawer lever, which has a pin 33 that engages with a surface cam (not shown) formed on the lower surface of the slave gear 25, and which is attached to a shaft 3 fixed to the chassis 7.
It is rotatably attached to 4. Note that a boss 35 that projects downward is formed on the lower surface of the slave gear 25.

36 is the first lever, 37 is this first lever 3
6, the first lever 36
has a pin 38 at one end that engages with a surface cam 19 formed on the gear 6 constituting the main side gear, and
The other end has a long hole 39 and is rotatably mounted on a shaft 40 fixed to the chassis 7, and the second lever 37 has a pin 41 that engages with the long hole 39 of the first lever 36. It also has the aforementioned boss 35 on the side.
It has a protrusion 42 that can be engaged with the chassis 7, and is rotatably mounted on a shaft 43 fixed to the chassis 7. The first lever 36 and the second lever 37 described above
constitutes an engagement release means for disengaging the gear 6 and the slave gear 25 in conjunction with the rotation of the gear 6 constituting the main gear.

Further, a spring 44 is held by the shaft 43, has one end engaged with the second lever 37, and extends in the direction of the slave gear 25 so that the other end can contact the boss 35 of the slave gear 25. This spring 44 is a means capable of biasing the subordinate gear 25 to rotate in the direction of the arrow 45 in FIG. It constitutes force applying means for applying force to the subordinate gear 25.

The operation of the conventional example configured in this way is as follows.

That is, in the ejected state before the cassette is installed at a predetermined installation position, the pin 17 of the cassette installation lever 15 is at position 1 of the portion 13 of the surface cam 10 of the worm wheel 5 shown in FIG.
It is in 1. Further, the gear 6 constituting the main gear and the slave gear 25 have a positional relationship as shown in FIG. 5a.
At this time, the first
The pin 38 of the second lever 36 is engaged, the protrusion 42 of the second lever 37 is in contact with the boss 35 of the slave gear 25, and the spring 44 is in contact with the boss 35. That is, the boss 35 is held between the protrusion 42 of the second lever 37 and the spring 44.

From this eject state, the motor 1 shown in Fig. 2
When the motor 1 is driven, the rotational force of the motor 1 is applied to the belt 3.
is transmitted to the pulley 2, worm 4, or worm wheel 5 via the worm wheel 5.
As the gear 6 rotates, the gear 6 constituting the main gear shifts to the fifth gear.
Rotate in the direction of arrow 47 in figure a. After approximately one revolution of the gear 6 in this manner, the pin 17 of the cassette mounting lever 15 passes from the position 11 of the surface cam 10 of the worm wheel 5 to the position 12 via the portion 13, and therefore the cassette shown in FIG. The mounting lever 15 rotates around the shaft 16 to place a cassette (not shown) at a predetermined mounting position, and the operation of the cassette device is completed.

Moreover, while such a gear 6 rotates approximately once,
The pin 38 of the first lever 36 passes through the part 20 of the face cam 19 and reaches the part 22, but the pin 38 and the part 2
The first lever 36 does not rotate while the boss 3 is engaged with the boss 3 as shown in FIG. 5a.
5 is held between the protrusion 42 of the second lever 37 and the spring 44, the slave gear 25 does not rotate, and as the pin 38 engages the portion 22, the first lever 36 is centered on the axis 40 in Fig. 5a.
Rotate in the direction of arrow 48, and remove the elongated hole 39 and pin 4.
1 , the second lever 37 rotates about the shaft 43 in the direction of arrow 49 , whereby the protrusion 42 of the second lever 37 engages with the boss 35 of the slave gear 25 .
5a, and the slave gear 25 is urged in the direction of arrow 50 in FIG. 5a by the force of the spring 44, leading to the state shown in FIG. 5b.

Further, when the motor 1 is driven from the state shown in FIG.
Corresponding to the rotation of the gear 6 which is less than one rotation, the slave gear 25 rotates less than one rotation in the direction of the arrow 45 in FIG. 5b, and as shown in FIG. The state shown is reached. During this time, the slave gear 25
Pin 3 that engages with surface cams (not shown) on the upper and lower surfaces of
0 and 33 move, and the pinch roller moving lever 2
9 rotates, a pinch roller (not shown) moves,
The pinch roller pinches the tape in the cassette and presses it against the capstan, and the tape pull-out lever 32 rotates to pull out the tape in the cassette, and a loading operation is performed in which the tape is wound around a drum cylinder (not shown). It will be done.
Note that during the transition from the state shown in FIG. 5b to the state shown in FIG. 5c, the cassette loading lever 1 is
5 pin 17 is the worm wheel 5 shown in FIG.
Since it engages with the portion 14 of the surface cam 10, no rotation occurs and the cassette is kept in a stable mounted state.

In this manner, the cassette loading operation, the pinch roller moving operation, and the tape drawing operation are performed.

Furthermore, in order to eject the cassette from the state shown in FIG. 5c, the motor 1 shown in FIG. 2 may be rotated in the opposite direction to that described above. This motor 1
As the gear 6 rotates, the gear 6 shown in FIG.
The slave gear 25 rotates in the direction of the arrow 54, and as the slave gear 25 rotates, the pinch roller moving lever 29 and the tape pull-out lever 32 rotate, and the pinch roller is removed from the capstan. The tape is moved away and the tape is pulled back into the cassette. During this time, the worm wheel 5 also rotates together with the gear 6 in the direction of arrow 55 in FIG. 4, and although the cassette mounting lever 15 does not rotate, the pin 17 reaches the position 12 of the surface cam 10.

When the motor 1 further rotates, the gear 6 rotates in the direction of the arrow 56 in FIG. During this time, as the pin 3 moves, the first lever 36 rotates about the shaft 40 in the direction of arrow 57, and as the first lever 36 rotates, the second lever 37 rotates in the direction of arrow 58. The protruding portion 42 contacts the boss 35 of the subordinate gear 25. Therefore, when the gear 6 rotates after the pin 38 engages with the portion 20 of the surface cam 19, the slave gear 25 is kept in a restrained state, and finally reaches the state shown in FIG. 5a. . During this period, the worm wheel 5 rotates together with the rotation of the gear 6, but the pin 17 of the cassette mounting lever 15 moves from position 12 to position 11 shown in FIG. It rotates and an eject operation is performed.

In the conventional example configured in this way, 1
The cassette loading lever 15, the pinch roller moving lever 29, and the tape pulling lever 32 can be driven by only one motor 1, and the number of driving sources can be minimized.

In addition, in this conventional example, since a non-gear portion 24 corresponding to the addendum circle is provided in a part of the gear 6, when the tooth portion 51 and the tooth portion 52 are engaged with each other as shown in FIG. , the effects of manufacturing errors between the pin 38 and the surface cam 19, such as backlash, and manufacturing errors of the first lever 36 and the second lever 37, are absorbed, and the teeth 51 and 52 are securely connected to each other. Can be interlocked.

By the way, in the conventional example as described above, the biasing force of the spring 44 is used to engage the subordinate gear 25 with the gear 6, but the biasing force of the spring 44 is A sensor (not shown) provided for detecting the sliding load on the surface cam portion of the pinch roller moving lever 29 and the tape pull-out lever 32, which have pins that engage with the surface cam on the lower surface, and the phase of the slave gear 25 The force must be greater than the contact sliding load of the mode identification switch. Further, if the spring 44 having such a biasing force cannot be installed in a limited space, another elastic member will be used to bias the subordinate gear 25.

However, the fact that a biasing force of a predetermined magnitude or more is applied to the slave gear 25 means that when the protrusion 42 of the second lever 37 is in contact with the boss 35, for example, during an eject operation, The biasing force is transmitted to the first lever 36 via the second lever 37, and as a result, the surface cam 1 of the gear 6
There is a drawback that the sliding pressure of the pin 38 engaged with the pin 9 is undesirably increased, which impedes the smooth operation of the mechanism.

[Purpose of the invention]

The present invention has been made in view of the above points, and an object of the present invention is to eliminate the use of an elastic member such as a spring as a means for engaging the subordinate gear with the main gear, and thus to prevent the attachment of the elastic member. It is an object of the present invention to provide a drive device having gears in which there is no possibility that the smooth operation of the mechanism will be hindered due to forces.

[Summary of the invention]

In order to achieve this object, the present invention provides a main side gear having a non-gear part that is attached to a first shaft and capable of multiple rotations, and a main side gear that is attached to a second shaft and has a gear with respect to the main side gear. a slave gear that can be engaged with the slave gear; and an engagement/disengagement switching means that can engage and disengage the master gear and the slave gear in conjunction with the rotation of the master gear; While the distance between the shaft and the second shaft is kept constant and the main gear rotates a plurality of times, the slave gear
In a drive device having a gear that is adapted to rotate within a range of less than 100 degrees, the engagement/disengagement switching means rotates the slave gear by a predetermined amount by its own rotational force and engages the slave gear with the main gear. The lever is provided with a lever having a protrusion to be engaged and a protrusion to be disengaged, and a tapered part is formed in the non-gear part of the main side gear to provide a notch. The force applied to the driven gear when engaged with the gear is made inelastic.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1a and 1b are explanatory diagrams showing the operational relationship in a drive device according to an embodiment of the present invention, and are examples in which it is applied to a drive section of a VTR similar to the conventional example. Portions corresponding to those in FIG. 5 are denoted by the same reference numerals, and their explanations will be omitted as appropriate.

In FIG. 1, the elongated hole 39 of the first lever 36
The second lever 37 has a pin 41 that engages with the shaft and is rotatably attached to a shaft 43 fixed to the chassis (not shown).
Two protrusions 60 and 61 are provided in the shape, and in the eject state before the cassette is installed in a predetermined installation position, the left side of the second lever 37 as shown in FIG. The protrusion 60 contacts the boss 35 of the slave gear 25 and restricts the rotation of the slave gear 25 in the direction of arrow 50, so the slave gear 25 engages with the gear 6 constituting the main gear. I can't.

In addition, a non-gear portion 24 provided on the circumferential side of the gear 6
The second lever 37 is made up of a circular arc portion corresponding to the tip circle and a tapered portion continuous thereto, and the second lever 37 is rotated approximately once in the direction of the arrow 47 from the ejected state shown in FIG. 1a. When the second lever 37 is rotated in the direction of arrow 49, the protrusion 60 on the left side in the figure separates from the boss 35 of the follower gear 25, and the protrusion 61 on the right side in the figure presses the boss 35 to release the second lever 37 from the boss 35. The side gear 25 is rotated by a predetermined amount in the direction of the arrow 50, and as a result, as shown in FIG. One tooth portion 52 of is positioned. That is, when a motor (not shown) is driven to rotate the gear 6 approximately one revolution from the state shown in FIG.
A cassette mounting lever (not shown) that engages with a surface cam on the top surface rotates to place the cassette in a predetermined mounting position, and also engages with a surface cam 19 on the bottom surface of gear 6. The first lever 36 is connected to the pin 3
8 passes through the section 20 and reaches the section 22. However, while the pin 38 and the section 20 are engaged, the first lever 36 does not rotate, and therefore, as shown in FIG.
As shown in , the boss 35 is kept in contact with the protrusion 60 of the second lever 37 on the left side in the figure, and the slave gear 25 does not rotate. Then, as the pin 38 engages the portion 22, the first lever 36 moves toward the shaft 40.
Rotate in the direction of arrow 48 in Fig. 1a around .
Therefore, the second lever 37 rotates in the direction of the arrow 49 about the shaft 43 via the elongated hole 39 and the pin 41, and as a result, the protrusion 60 on the left side of the second lever 37 in the figure separates from the boss 35. , the protrusion 61 on the right side in the figure contacts and presses the boss 35 due to its own rotational force of the second lever 37;
This pressing force causes the slave gear 25 to rotate by a predetermined amount in the direction of arrow 50 in FIG. 1a, resulting in the state shown in FIG. 1b. In this way, as shown in FIG.
When the gear 6 further rotates in the direction of arrow 46 after being fed into the notch 62 of After this, the subordinate gear 25 also rotates within a range of less than one revolution corresponding to the rotation of the gear 6 within a range of less than one revolution, thereby causing the upper and lower surfaces of the slave gear 25 to rotate. A pinch roller moving lever and a tape drawing lever (not shown) that are engaged with the cam are operated.

In addition, when ejecting the cassette after the cassette mounting operation, pinch roller movement operation, and tape drawing operation have been completed in this way, the motor is rotated in the opposite direction to the gear 6.
is rotated in the direction of arrow 56 in FIG. As it moves away, the tape is pulled back into the cassette. Then, the gear 6 is further rotated in the direction of the arrow 56, and the pin 3 of the first lever 36 is rotated.
8 reaches the portion 20 of the surface cam 19 from the portion 22, the first lever 36 moves along the arrow 57 about the shaft 40.
As a result, the second lever 37 rotates in the direction of the arrow 58, and the protruding portion 60 of the second lever 37 on the left side in the drawing comes into contact with the boss 35 of the slave gear 25. Therefore, during the rotation of the gear 6 after the pin 38 has engaged with the portion 20 of the face cam 19, the slave gear 25 remains stationary, resulting in the state shown in FIG. 1a. . Moreover, during this eject operation, during the transition from the state shown in FIG. 1b to the state shown in FIG.
7, the protrusion 60 on the left side of the figure can be smoothly moved to a predetermined position by abutting against the boss 35. In other words, unlike the conventional example described above, the boss 35 can be moved against the urging force of the elastic member as in the conventional example described above. Therefore, there is no risk that the sliding pressure of the pin 38 engaged with the surface cam 19 will be undesirably increased due to the influence of this type of biasing force, and the mechanism can always operate smoothly. It can be realized.

〔Effect of the invention〕

As explained above, according to the present invention, by providing a lever having a protrusion that rotates the slave gear by a predetermined amount by its rotational force and engages it with the master gear, the slave gear This eliminates the need for elastic members such as springs, which were conventionally used as a means for engaging the gear with the main gear, and therefore eliminates the need for smooth mechanism operation due to the biasing force of the elastic member. There is no problem and the lever described above can be easily realized by making a slight change to the shape of the lever used as the engagement/disengagement switching means in conventional products, so there is no need to worry about an increase in the number of parts. Nor.

[Brief explanation of drawings]

FIGS. 1a and 1b are explanatory diagrams showing the operational relationship in a drive device according to an embodiment of the present invention, and FIG.
Figures a, b, and c are for explaining a conventional example, and Figure 2 is a plan view, and Figure 4 is a plan view showing a worm wheel provided in the drive device shown in Figures 2 and 3. , and FIGS. 5a to 5c are explanatory diagrams showing the operational relationship in the drive device shown in FIGS. 2 and 3. 6... Gear, 8... First shaft, 19... Face cam, 23, 27... Gear part, 24, 28... Non-gear part, 25... Follower gear, 26... Second shaft ,3
5... Boss, 36... First lever, 37... Second lever, 38, 41... Pin, 39... Elongated hole, 40, 43... Shaft, 51, 52... Teeth, 6
0, 61...protrusion, 62...notch.

Claims (1)

[Claims] 1 A main side gear having a non-gear part that is attached to a first shaft and capable of multiple rotations, a subordinate gear that is attached to a second axis and can mesh with the main side gear, and the above main side gear. an engagement/disengagement switching means capable of engaging and disengaging the main gear and the slave gear in conjunction with the rotation of the gear, and an engagement/disengagement switching device capable of engaging and disengaging the main gear and the slave gear in conjunction with the rotation of the gear; In a drive device having a gear in which the distance is kept constant and the slave gear rotates less than one revolution via the engagement/disengagement switching means while the main gear rotates a plurality of times. , the engagement/disengagement switching means includes a lever having a protrusion that rotates the slave gear by a predetermined amount by its rotational force to engage the slave gear with the main gear and a protrusion that disengages the slave gear; 1. A drive device having a gear, characterized in that a non-gear portion of the main gear is provided with a tapered portion and a notch.