JPH05174466A - Tape threading device - Google Patents

Abstract

PURPOSE:To obtain unthreading operation suitable for an ewergent time. CONSTITUTION:This device is provided with a transmission mechanism 44 coupled with a driving gear 26 and having a worm wheel 47 transmitting driving force and a worm gear 54 coupled with the transmission mechanism 44 and rotated by a motor 49, and the worm gear 54 is formed by the worm gear having two tooth parts 54a, 54b of large and small whose respective lead angles are different each other. The tooth part 54b whose lead angle is small between both tooth parts of the worm gear is engaged with tree worm wheel 47 and the worm wheel 48 transmitting hand driving force is engaged with the tooth part 54a whose lead angle is large. Thus, an operational time at the time of transmitting rotational force necessary for unthreading operation to the worm wheel 47 is shortened because the worm wheel 48 is rotated by manual operation and the rotational force is transmitted to the driving gear 26 through the transmission mechanism 44 from the tooth part 54a of the worm gear 54.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tape slitting apparatus suitable for application to recording / reproducing equipment such as a video tape recorder.

[0002]

2. Description of the Related Art Generally, a video tape recorder (hereinafter referred to as
It is called "VTR". The tape slitting device of (1) is known to include a worm gear as a speed reducing mechanism of a drive motor because a relatively large speed reduction ratio and high speed rotation can be obtained in a small space.

Conventionally, this type of tape slitting apparatus has a transmission mechanism having a worm wheel for transmitting a motor driving force connected to a drive gear for tape slitting / unsletting, and a worm gear connected to this transmission mechanism and rotated by a motor. The one with and is adopted.

In the tape slitting apparatus having such a structure, the drive motor (slotting motor) performs the slitting operation and the unthreading operation.

By the way, for example, V used in broadcasting stations
In the tape tape slitting device of TR, it is necessary that not only the unthreading operation can be performed by the drive motor but also the manual operation so that the tape jamming or the like can be dealt with in an emergency.

[0006]

However, in the conventional tape slitting device, since the driving force of the motor is transmitted from the worm gear to the worm wheel of the transmission mechanism, the worm gear is manually rotated in an emergency. The unthreading operation was performed by transmitting the rotational force to the worm wheel. That is, the lead angle γ of the worm gear meshing with the worm wheel of the transmission mechanism is set to an angle that satisfies the inequality of γ <μ / cosα (μ and α are the friction coefficient and the pressure angle, respectively). Therefore, the worm wheel cannot be directly rotated manually, and the worm gear must be rotated during the manual unthreading operation. As a result, there has been a problem that it takes a lot of operation time to transmit the rotational force required for the unsletting operation to the worm wheel of the transmission mechanism, and it is not possible to obtain an unsletting operation adapted to an emergency.

The present invention has been made in view of the above circumstances, and it is possible to shorten the operation time when transmitting the rotational force necessary for the unthreading operation to the worm wheel of the transmission mechanism, and thus, to perform an emergency. An object of the present invention is to provide a tape slitting device that can obtain an unthreading operation that is sometimes adapted.

[0008]

SUMMARY OF THE INVENTION A tape slitting device according to the present invention includes a transmission mechanism having a worm wheel for transmitting a motor driving force, the transmission mechanism being connected to a drive gear for tape slitting / unsletting. A worm gear rotated by a motor, and the worm gear is formed by a worm gear having two large and small tooth portions each having a different lead angle, and the tooth portion having a smaller lead angle is transmitted to the motor drive force. A worm wheel for manual transmission is meshed with a worm wheel for manual force transmission.

[0009]

In the present invention, the worm wheel for manual force transmission can be manually rotated to transmit the rotational force to the worm gear.

[0010]

Embodiments of the present invention will be described in detail below with reference to embodiments shown in the drawings.

1 (A) and 1 (B) are a plan view and a side view showing a main part of a tape slitting apparatus according to the present invention.
FIG. 2 is a plan view showing the entire tape slitting device of the present invention, and FIG. 3 is a plan view showing the connection state of the worm gear and the motor shaft of the tape slitting device of the present invention.

In FIG. 1, reference numeral 1 denotes a drum having a rotary head chip (not shown), which is provided inside an equipment casing (not shown) and has a threading state on a part of its outer peripheral surface. At, the magnetic tape 3 in the cassette 2 is wound.

Reference numeral 4 denotes a rail having a main rail plate 5 and sub-rail blocks 6 and 7, which is provided around the drum 1 and fixed to a chassis (not shown) with screws 8 and is provided on both sides of the rail. Are formed with guide grooves 9 and 10 having openings 9a and 10a which are substantially fishhook-like in plan view.

Sub rail blocks 6 and 7 of this rail 4
The stopper plates 11 and 12 having V-shaped recesses 11a and 12a in plan view, which communicate with the threading-side tip portion 9b of the guide groove 9 and the threading-side tip portion 10b of the guide groove 10, are fixed thereto. There is. Further, on the supply side of the rail 4, there is formed a groove 13 for guiding the pin, which opens upward.

Reference numeral 14 denotes a supply side guide assembly having a roller guide 14a and an inclined guide 14b, which is connected to a slider 15 facing the front opening edge of the guide groove 9 and the slider 15 via a first positioning pin 16. And a slider block (not shown) facing the opening edge on the back side of the guide groove 9, and is movably provided on the rail 4. The guide assembly 14 is provided with a guide pin 17 that faces the groove 13 and a second positioning pin 18 that can be fitted into the recess 11a.

Reference numeral 19 denotes a winding side guide assembly having a roller guide 19a and an inclined guide 19b, and a slider 20 facing the front opening edge of the guide groove 10 and a first positioning pin 21 on the slider 20. It is composed of a slider block (not shown) that is connected and faces the opening edge on the back side of the guide groove 10, and is movably provided on the rail 4. In the guide assembly 19, the leading pin 22 and the recess 1 facing the guide groove 10 are provided.
The 2nd positioning pin 23 which can be fitted in 2a is provided.

Numerals 24 and 25 are two gear pivots arranged in parallel at a predetermined interval, which are provided below the rail 4 and fixed on the chassis (not shown).

26 and 27 are each an intermediate gear 2 with respect to each other.
Drive gears meshing with each other through the gear shafts 24,
25 is rotatably provided. Each of these drive gears 2
6 and 27, a concave portion 26 that is circular in a plan view and opens at the upper end surface
a, 27a are formed, and these concave portions 26a, 2a are formed.
On the inner peripheral surface of 7a, drive projections 29, 30 capable of pressing one end of a limiter spring, which will be described later, are integrally provided. In addition, the recesses 26a of the drive gears 26 and 27,
Cylindrical bosses 31 and 32, which face the respective gear pivots 24 and 25, are integrally provided inside 27a.

Limiter springs 33 and 34 are torsion coil springs, and are mounted on the outer peripheral surfaces of the bosses 31 and 32. Both ends of each of the limiter springs 33 and 34 are projected in the boss radial direction from different boss circumferential positions.

Reference numeral 35 denotes a supply side drive arm having a driven protrusion 35a, which is swingably provided on the boss 31.

Reference numeral 36 is a guide driving link mechanism on the supply side, and a first link 37 swingably connected to the end portion of the drive arm 35 opposite to the boss side, and a swingable connection to the first link 37. Intermediate link 38 that has been created and this intermediate link 3
8 and a second link 39 that is swingably connected to the first positioning pin 16 and applies a driving force to the guide assembly 14, and is movably provided below the rail 4. Of the pivot pins of the guide drive link mechanism 36, the pivot pin a between the intermediate link 38 and the second link 39 faces the guide groove 9.

Reference numeral 40 denotes a drive arm having a driven protrusion 40a, which is swingably provided on the boss 32.

Reference numeral 41 denotes a guide-driving link mechanism on the winding side, which includes a first link 42 swingably connected to the end portion of the drive arm 40 on the side opposite to the boss, and a swing mechanism capable of swinging to the first link 42. The second link 43 is connected to the guide assembly 19 and applies a driving force to the guide assembly 19. The second link 43 is movably provided to the side of the guide driving link mechanism 36. Of the pivot pins of the guide drive link mechanism 41, the pivot pins b of both links 42, 43 are supposed to face the inside of the guide groove 10.

A transmission mechanism 44 applies a motor driving force to the drive gear 26 via an intermediate gear 45. The transmission mechanism 44 has a cam groove 46a opened at the upper end surface and a boss 46b protruding at the lower end surface.
With a transmission gear 46, and a boss 47 that is juxtaposed in the radial direction of the transmission gear 46 at a predetermined interval and projects toward the lower end surface.
a worm wheel 47 having a, a boss 47 a of the worm wheel 46 and a boss 46 b of the transmission gear 46.
The timing belt B is stretched around the guide belt and is provided below the guide driving link mechanism 36.

Reference numeral 48 denotes a worm wheel for manual force transmission, which is rotatably arranged side by side at a predetermined interval in the radial direction of the worm wheel 47, and has a flat surface into which a screw driver (not shown) is inserted / removed at the upper end surface. A cruciform groove 48a is formed.

Reference numeral 49 is a motor for threading / unthreading, which has an output shaft 49a projecting in the cassette withdrawing direction, which is provided in the equipment casing (not shown) and on the chassis (not shown). It is fixed to the base 50.

Reference numeral 51 denotes a worm gear shaft extending in the cassette insertion / removal (front / rear) direction, one end of which is connected to the output shaft 49a of the motor 49 via a joint 52, and the other end of which is a radial portion on the base 50. It is supported by a bearing 53.

Reference numeral 54 denotes a worm gear rotated by the motor 49, which is press-fitted and fixed to the worm gear shaft 51. The worm gear 54 has two large and small tooth portions 54a and 54b having lead angles γ ₁ and γ ₂ which are different from each other, and the worm wheel 4 is provided on each of the tooth portions 54a and 55a.
8 and the worm wheel 46 are configured to mesh with each other.

The advance angles γ ₁ and γ ₂ of the tooth portions 54a and 54b are γ ₁ > μ / cos α and γ ₂ <μ / cos α, respectively.
The angles (γ ₁ = 20 °, γ ₂ = 5 °) are set so as to satisfy the inequalities of (the friction coefficient and the pressure angle are μ and α, respectively).

Reference numeral 56 denotes a tape pull-out arm mechanism on the supply side, which is rotatably provided on a tape pull-out arm 57 as a rotary arm having a tape guide 57a and a cam portion 57b, and a pivot support 58 of the tape pull-out arm 57. An auxiliary arm 59 having a cam groove 59a opened in the up-down direction, a cam groove 59a of the auxiliary arm 590, a first pin 60a facing the cam portion 57b of the tape pull-out arm 57, and a cam groove 46a of the transmission gear 46. It is composed of a rotating arm 59 having a second pin 59b, and is provided in the device housing (not shown).

Reference numeral 60 denotes a tape pull-out arm mechanism on the take-up side, which is provided in the equipment casing (not shown) and is connected to the drive gear 27 via a gear train 61 and a transmission mechanism 62. There is. The tape pull-out arm 63 of the tape pull-out arm mechanism 60 is provided with a tape guide 65 and a pinch roller 66, which are arranged in parallel via a connecting arm 64.

Further, 67 to 70 are fixing tape guides, 71 is a capstan, and 72 is a head such as an erasing head or a voice recording / reproducing head.

In the tape slitting device thus constructed, the worm wheel 48 for manual force transmission is manually rotated, and the rotational force is transmitted to the tooth portion 54a of the worm gear 54 and the transmission mechanism 44 (the worm wheel 4).
7, can be transmitted to the drive gear 26 via the timing belt B and the transmission gear 46). Here, for example, when the number of teeth of the worm wheel 48 and the number of teeth of the tooth portion 54a are "16" and "3", respectively, the worm wheel 4
When 8 rotates once, the worm gear 54 rotates 5.3 times.

Therefore, in this embodiment, in an emergency, the worm wheel 48 is rotated manually (screw driver) and the rotational force can be transmitted to the worm gear 54 to perform the unthreading operation. It is possible to shorten the operation time when transmitting the rotational force necessary for the unsletting operation to the worm wheel 47.

Further, in this embodiment, since the groove 48a is formed in the worm wheel 48, the unthreading operation can be performed by a screw driver (not shown), so that two threading threads adjacent to each other are used. It is extremely effective for unthreading operation when the space between system components is small.

Incidentally, in the present embodiment, the drive gears 26,
The transmission of the driving force to the 27 at the time of the threading operation and the unthreading operation by the motor 49 is performed as follows.

That is, the worm gear 54 is rotated by the forward and reverse rotations of the motor 49, and this rotational force is transmitted from the tooth portion 54b of the worm gear to the drive gear 26 via the transmission mechanism 44, and at the same time, from the drive gear 26 to the intermediate gear. 28
Is transmitted to the drive gear 27 via. At this time, the guide assemblies 14 and 19 and the tape pull-out arms 56 and 6
3 reciprocates between the threading position and the unthreading position. In this case, the rotational force of the motor 49 is also transmitted from the tooth portion 54a of the worm gear 54 to the worm wheel 48, but this worm wheel 48 is not meshed with a gear other than the worm gear 54, and therefore the load of the worm wheel 48 is increased. Does not mean

In the present embodiment, an example in which the present invention is applied to a VTR is shown, but the present invention is not limited to this application and can be applied to other recording / reproducing devices in the same manner as the embodiment. Is.

Further, the present invention is not limited to the above-described embodiments, but various effective modifications and changes can be made based on the technical idea of the present invention.

[0040]

As described above, according to the present invention, a transmission mechanism having a worm wheel for transmitting a motor driving force, which is connected to a drive gear for tape slitting / unsletting, and a motor connected to the transmission mechanism. A worm gear that rotates, the worm gear is formed by a worm gear having two large and small tooth portions each having a different lead angle, and the tooth portion having a smaller lead angle is used for transmitting the motor driving force. Since the worm wheel for manual force transmission was meshed with the tooth part with a large lead angle, it was manually meshed with the worm wheel, and the worm wheel for manual force transmission was manually rotated.
This rotational force can be transmitted to the drive gear through the transmission mechanism from the tooth portion of the worm gear having a large lead angle among the tooth portions.

Therefore, in the event of an emergency, the worm wheel for manual force transmission is manually rotated, and by transmitting this rotational force to the worm gear, the unthreading operation can be performed. Therefore, the unwheeling of the worm wheel of the transmission mechanism is performed. It is possible to shorten the operation time when transmitting the rotational force necessary for the operation, and it is possible to obtain the unthreading operation adapted in an emergency.

[Brief description of drawings]

1A and 1B are a plan view and a side view showing a main part of a tape threading device according to the present invention.

FIG. 2 is a plan view showing the entire tape threading device according to the present invention.

FIG. 3 is a plan view showing a connection state of a worm gear and a motor shaft of the tape threading device according to the present invention.

[Explanation of symbols]

26 ... Drive gear, 44 ... Transmission mechanism, 47, 48 ... Worm wheel, 49 ... Motor, 54 ... Worm gear, 54
a, 54b ... Tooth portion.

Claims (1)

[Claims] 1. A transmission mechanism having a worm wheel for transmitting a motor driving force which is connected to a drive gear for tape slitting / unsletting, and a worm gear which is connected to the transmission mechanism and is rotated by a motor. It is formed by a worm gear having two large and small tooth portions each having a different lead angle, the tooth portion having a smaller lead angle of both tooth portions of the worm gear is meshed with the worm wheel, and the tooth portion having a larger lead angle is manually operated. A tape threading device characterized by engaging a worm wheel for transmission.