JP2983681B2 - Swing lever type reel base drive mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reel drive mechanism for a VTR.

[0002]

2. Description of the Related Art As shown in FIGS.
The swinging lever type reel stand driving device that selectively rotates the supply reel stand (1) and the take-up reel stand (11) of the VTR according to the mode switching is provided between the two reel stands (1) and (11). A swing lever (2) is provided so as to be rotatable about a fulcrum shaft (21).

As shown in FIG. 3, first and second gears (41) and (42) are rotatable independently of each other in two stages vertically and concentrically with a fulcrum shaft (21) of a swing lever (2). 1st by plate (51)
They are connected and arranged via a slip mechanism (5). A third gear (43) meshing with the second gear (42) and selectively meshing with the supply reel table (1) and the take-up reel table (11) is pivotally connected to the free end of the swing lever (2). Support.

A felt plate (61) is interposed between the third gear (43) and the swing lever (2) to constitute a second slip mechanism (6).

A drive gear (3), which can selectively mesh with both gears (41) and (42), can be moved up and down near the first gear (41) and the second gear (42) of the swing lever (2). Has been deployed. Drive gear
By switching the rotation direction in (3), the swing lever (2) is rotated, and the third gear (43) is engaged with one of the reel bases and driven to rotate.

The first gear (41) and the second gear (42) generate slip torque between the two gears (41) and (42) by the first slip mechanism (5). Rotate for free. The first slip mechanism (5) serves to drive the reel base with a constant torque. The second slip mechanism (6) includes a third gear (43).
The lever (2) is moved to the second position by preventing the
It has the function of swinging and rotating in the rotation direction of the gear (42), that is, the role of switching the power transmission path.

In the above-mentioned swing lever type reel stand drive mechanism, there is no particular problem during the swing operation.
The third gear (43) is a supply reel base (1) or a take-up reel base (11).
When the reel base is driven by meshing with the third gear (4
3) is slipping with respect to the swing lever (2), and the slip is completely lost with respect to the original reel base driving torque.

Therefore, the first slip mechanism (5) for obtaining a constant reel base driving torque sets a high torque in advance in anticipation of the loss of torque by the second slip mechanism (6) for swinging. It has to do so, which hinders downsizing of the mechanism, and has a problem in reliability. Further, a large-capacity motor (not shown) is required, which is disadvantageous in terms of power consumption.

Further, since the relative rotation speed of the friction surface in the second slip mechanism (5) for swinging is equal to the rotation speed of the third gear (43), the fast forward / rewind mode, the fast forward reproduction / If the reel base is driven to rotate at high speed in order to increase the speed of the rewind reproduction mode, durability becomes a problem.

The present invention clarifies a swing lever type reel base driving mechanism which solves the above-mentioned problems of the conventional mechanism.

[0011]

According to the swing lever type reel stand driving mechanism of the present invention, a swing lever (2) is rotatably provided between a supply reel stand (1) and a take-up reel stand (11). Then lever
The first and second gears (41) and (42) are arranged rotatably independently of each other in two upper and lower stages concentrically with the rotation fulcrum shaft (21) of (2).
(41) A first slip mechanism (5) that slips when a load exceeding a certain level acts between the second gear (42) and the second gear (42) is engaged with the free end of the lever (2). A third gear (43) that can selectively mesh with the reel base (1) and the take-up reel base (11) is pivotally supported, and a driving gear is selectively connected to the first and second gears (41) and (42).
(3) is engaged, the lever (2) is swung by switching the direction of rotation of the drive gear (3), and the third gear (43) is engaged with one of the reel bases, and the reel base is rotationally driven. In the driving device, a fourth gear (44) is rotatably disposed coaxially with the third gear (43), meshes with the first gear (41), and the third gear (47) and the fourth gear (44). ), A second slip mechanism (6) that slips when a load exceeding a certain level acts on the first gear.
From the reduction ratio of (41) to the fourth gear (44),
The reduction ratio from (42) to the third gear (43) is larger,
Also, the first torque is smaller than the slip torque of the second slip mechanism (6).
The slip torque is large.

[0012]

[Operation and Effect] The driving force transmitted from the driving gear (3) to the first gear (41) drives the fourth gear (44) at the same time as the first driving.
The second gear (42) is driven via the slip mechanism (5), and the third gear (43) is further driven.

Here, when the first slip mechanism (5) between the first gear (41) and the second gear (42) is not slipping,
The fourth gear (44) tends to rotate at a higher speed than the third gear (43) from the relation of the reduction ratio.

Since a frictional force is generated between the fourth gear (44) and the third gear (43) via the second slip mechanism (6),
A load acts due to a speed difference between the fourth gear (44) and the third gear (43).

Therefore, the state in which the swing lever (2) rotates freely, that is, when the third gear (43) is in the supply reel stage (1) or
In a state in which the first gear (41) and the second gear (42) are rotated in a state where they are not engaged with the take-up reel base (11) (see FIG. 5), the fourth gear (44) and the third gear (43) are rotated. Is the pivot axis (22)
Without turning, the swing lever (2) is pivoted on the fulcrum shaft (21).
Rotate against.

The direction of rotation of the swing lever (2) is determined by the drive gear.
(3) Therefore, it is determined by the rotation direction of the first gear (41).
When the first gear (41) rotates clockwise, the lever (2) also rotates clockwise, and the third gear (43) meshes with the take-up reel base (11), as shown in FIG. When (41) rotates counterclockwise, the lever (2) also rotates counterclockwise, and the third gear
(43) meshes with the supply reel base (1).

When the third gear (43) engages with the supply reel base (1) or the take-up reel base (11), and the rotation of the swing lever (2) stops, a load is applied to the mating reel base. The first slip mechanism having a high slip torque
(5) That is, the second slip mechanism (6) which does not slip between the first gear (41) and the second gear (42) and has a low slip torque,
That is, a slip occurs between the fourth gear (44) and the third gear (43), and the third gear (43) is connected to the supply reel table (1) or the take-up reel table.
(11) is driven.

This state appears during the transition to the mode or when the tape is dropped. In a mode in which the tape is transported at a constant speed by the pinch roller and the capstan, such as a play mode, a fast-forward playback mode, and a rewind playback mode, the third mode is used.
A constant torque is applied to the supply reel table on the opposite side of the reel table (here, the take-up reel table) forcibly driven by the gear (43), and the rotation speed of the reel table changes depending on the tape winding diameter. However, it is necessary to always wind the tape so that it does not hang.

Therefore, in this mode, the take-up reel base (11) is rotated at a higher rotational speed than the maximum rotational speed of the take-up reel base (11).
By driving the first gear (41) at a rotational speed capable of driving the (11), the distance between the first gear (41) and the second gear (42) is reduced.
And a slip occurs between the fourth gear (44) and the third gear (43).

That is, the slip torque between the first gear (41) and the second gear (42) is applied to the take-up reel table (11) from the second gear (42) via the third gear (43). A transmission path, and rotation is transmitted from the first gear (41) to the fourth gear (44).
The slip torque between 4) and the third gear (43) is transmitted to the third gear (43), and the torque is transmitted through two paths of the torque transmission path to the take-up reel table.

Accordingly, the slip torque of both the first slip mechanism (5) and the second slip mechanism (6) becomes a torque for driving the reel base, and the torque transmitted to the swing in this state is a loss in this state. Not to help drive the reel stand.

[0022]

FIG. 1 is a sectional view showing an example of a reel base driving mechanism according to the present invention. FIG. 1 shows a mode in which the reel base is driven with a constant torque, such as a play mode, a fast-forward playback mode, and a rewind playback mode. A swing lever (2) is rotatably provided between the supply reel table (1) and the take-up reel table (11).

A large-diameter first gear (41) and a small-diameter second gear (42) are rotatably arranged in two stages and independently of each other on a fulcrum shaft (21) of the lever (2). The felt plate (51) adhered to the gear (42) is brought into contact with the first gear (41) and the spring (5
In 2), the first gear (41) is urged to the second gear (42) to constitute the first slip mechanism (5).

On a pivot (22) provided at the free end of the lever (2), a third gear (43) meshable with the second gear (42) and a fourth gear meshable with the first gear (44). The gear (44) is freely rotatable, the felt plate (61) adhered to the fourth gear (44) is brought into contact with the third gear (43), and the third gear (4) is moved by the spring (62).
3) is urged to the fourth gear (44) to constitute the second slip mechanism (6).

Each slip mechanism is configured so that the slip torque of the first slip mechanism (5) is larger than the slip torque of the second slip mechanism (6). Third gear (43)
Are located at the same height as the tooth surface (12) of the reel bases (1) and (12).

In the vicinity of the first gear (41) and the second gear (42), a rotary drive gear (3) connected to a motor (not shown) is provided so as to be vertically movable in accordance with mode switching. . Drive gear
In (3), the small-diameter gear (31) and the large-diameter gear (32) are formed in two stages, upper and lower. In the mode shown in FIG. Is engaged.

As described above, the second gear is shifted more than the first gear (41).
Since the pitch circle diameter of (42) is smaller, the gear train of the second gear (42) and the third gear (43) is more suitable than the gear train of the first gear (41) and the fourth gear (44). Has a large reduction ratio.

However, the driving force transmitted from the driving gear (3) to the first gear (41) drives the fourth gear (44) and at the same time simultaneously drives the second gear (42) via the first slip mechanism (5). ),
Further, the third gear (43) is driven.

Here, when the first slip mechanism (5) between the first gear (41) and the second gear (42) is not slipping,
The fourth gear (44) tends to rotate at a higher speed than the third gear (43) from the relation of the reduction ratio. Since a frictional force is generated between the fourth gear (44) and the third gear (43) via the second slip mechanism (6), the frictional force is generated between the fourth gear (44) and the third gear (43). The load caused by the difference in speed acts on the vehicle.

Therefore, the state in which the swing lever (2) is free to rotate, that is, the third gear (43) is in the supply reel stage (1) or
In a state in which the first gear (41) and the second gear (42) are rotated in a state where they are not engaged with the take-up reel base (11) (see FIG. 5), the fourth gear (44) and the third gear (43) are rotated. Is the pivot axis (22)
Without turning, the swing lever (2) is pivoted on the fulcrum shaft (21).
Rotate against.

The direction of rotation of the swing lever (2) is determined by the drive gear.
(3) Therefore, it is determined by the rotation direction of the first gear (41).
When the first gear (41) rotates clockwise, the lever (2) also rotates clockwise, and the third gear (43) meshes with the take-up reel base (11), as shown in FIG. When (41) rotates counterclockwise, the lever (2) also rotates counterclockwise, and the third gear
(43) meshes with the supply reel base (1).

When the third gear (43) meshes with the supply reel table (1) or the take-up reel table (11) and the rotation of the swing lever (2) stops, a load is applied to the mating reel table. The first slip mechanism having a high slip torque
(5) That is, the second slip mechanism (6) which does not slip between the first gear (41) and the second gear (42) and has a low slip torque,
That is, a slip occurs between the fourth gear (44) and the third gear (43), and the third gear (43) is connected to the supply reel table (1) or the take-up reel table.
(11) is driven.

This state appears during the transition to the mode or at the time of tape dripping. In a mode in which the tape is transported at a constant speed by the pinch roller and the capstan, such as a play mode, a fast-forward playback mode, and a rewind playback mode, the third mode is used.
A constant torque is applied to the supply reel table on the opposite side of the reel table (here, the take-up reel table) forcibly driven by the gear (43), and the rotation speed of the reel table changes depending on the tape winding diameter. However, it is necessary to always wind the tape so that it does not hang.

Therefore, in this mode, the take-up reel base (11) is rotated at a higher rotational speed than the maximum rotational speed of the take-up reel base (11).
By driving the first gear (41) at a rotational speed capable of driving the (11), the distance between the first gear (41) and the second gear (42) is reduced.
And a slip occurs between the fourth gear (44) and the third gear (43).

That is, the slip torque between the first gear (41) and the second gear (42) is applied to the take-up reel table (11) from the second gear (42) via the third gear (43). A transmission path, and rotation is transmitted from the first gear (41) to the fourth gear (44).
The slip torque between 4) and the third gear (43) is transmitted to the third gear (43), and the torque is transmitted through two paths of the torque transmission path to the take-up reel table.

Therefore, the slip torque of both the first slip mechanism (5) and the second slip mechanism (6) is the torque for driving the reel base.

The above point is the most different feature of the mechanism according to the present invention from the conventional mechanism. The loss of the second swing mechanism (6) for swinging which has been a problem in the conventional mechanism is eliminated, and the first gear (41) is eliminated. The torque of the first slip mechanism (5) between the first and second gears (42) can be reduced, which is advantageous for reducing the size and weight of the mechanism and improving reliability.

Further, the load on the driving motor is reduced, so that a small motor can be used, and the power consumption can be reduced.

On the other hand, in a mode such as a fast-forward / rewind mode in which the torque of the motor must be transmitted directly without passing through a slip mechanism, as shown in FIG.
By sliding (3) upward in the axial direction, the rotation transmission path is switched to drive the third gear (42) from the second gear (42).

At this time, the slip torque between the first gear (41) and the second gear (42) is larger than the slip torque between the fourth gear (44) and the third gear (43). The second gear (42) is directly moved to the third gear (43) from the point in time when the take-up reel stand (11) and the third gear (43) mesh with each other.
Drive. For this reason, a slip occurs between the fourth gear (44) and the third gear (43), and in this state, the slip torque is lost with respect to the reel drive.

However, at this time, the relative rotation speed between the felt plate (61) of the second slip mechanism (6) and the third gear (43) is the same as that of the fourth gear (44) and the third gear (43). This is the difference between the rotation speeds, and is much smaller than the actual rotation speed of the third gear (43). Therefore, the reliability of the slip mechanism for swinging the head is greatly improved as compared with the conventional mechanism.

The present invention is not limited to the configuration of the above embodiment, and various modifications can be made within the scope of the claims.

[Brief description of the drawings]

FIG. 1 is a sectional view of a reel base driving mechanism according to the present invention.

FIG. 2 is a cross-sectional view in a fast-forward / rewind mode according to the first embodiment;

FIG. 3 is a sectional view of a conventional reel base driving device.

FIG. 4 is a plan view of a drive mechanism in a state where the take-up reel base is driven.

FIG. 5 is a plan view of a drive mechanism in the process of turning the swing lever.

[Explanation of symbols]

 (1) Supply reel table (2) Take-up reel table (3) Swing lever (3) Drive gear (41) First gear (42) Second gear (43) Third gear (44) Fourth gear (5 ) First slip mechanism (6) Second slip mechanism

Claims (1)

(57) [Claims] A swing lever (2) is rotatably provided between a supply reel table (1) and a take-up reel table (11).
The first and second gears (41) and (42) are arranged rotatably independently of each other in two upper and lower stages concentrically with the rotation fulcrum shaft (21) of (2).
(41) A first slip mechanism (5) that slips when a load exceeding a certain level acts between the second gear (42) and the second gear (42) is engaged with the free end of the lever (2). A third gear (43) that can selectively mesh with the reel base (1) and the take-up reel base (11) is pivotally supported, and a driving gear is selectively connected to the first and second gears (41) and (42).
(3) is engaged, the lever (2) is swung by switching the direction of rotation of the drive gear (3), and the third gear (43) is engaged with one of the reel bases, and the reel base is rotationally driven. In the driving device, a fourth gear (44) is rotatably disposed coaxially with the third gear (43), meshes with the first gear (41), and the third gear (47) and the fourth gear (44). ), A second slip mechanism (6) that slips when a load exceeding a certain level acts on the first gear.
From the reduction ratio of (41) to the fourth gear (44),
The reduction ratio from (42) to the third gear (43) is larger,
Also, the first torque is smaller than the slip torque of the second slip mechanism (6).
A swing lever type reel stand drive device characterized by a large slip torque.