192 clutches and power-stop control – Clutches – Plural clutch-assemblage
Reexamination Certificate
2003-01-27
2004-06-01
Rodriguez, Saúl (Department: 3681)
192 clutches and power-stop control
Clutches
Plural clutch-assemblage
C192S048500, C242S356300, C242S356500, C360S096300, C360S096400
Reexamination Certificate
active
06742641
ABSTRACT:
The present disclosure relates to the subject matter contained in Japanese Utility Model Application No. U2002-000337 filed Jan. 29, 2002, which is incorporated herein by reference in its entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a rotational driving apparatus of a magnetic tape device, particularly to a rotational driving apparatus capable of rapidly forwarding and rewinding a magnetic tape.
2. Description of the Related Art
Fast forwarding and rewinding of a magnetic tape device are carried out frequently, such as when finishing a reproduction, or when selecting images. In order to carry out such the fast forwarding and rewinding of a magnetic tape, it is necessary that the magnetic tape be made to run at a speed higher than a normal level.
It is conceivable to set a reduction ratio in a rotation transmission path extending from a motor to a reel low so as to increase a rotational speed of the reel. However, if the reduction ratio is set too low, the motor need to be rotated at a very low speed during a normal reproduction operation. As a result, the rotational stability of the reel during the reproduction operation is deteriorated. This may cause a disarrangement of a reproduced picture image or a deterioration of the quality of a reproduced picture image.
A magnetic tape device capable of carrying out rapid forwarding and rewinding of a magnetic tape is provided with a mechanism for transmitting a motor rotation to a reel through a transmission path different from that used during a reproduction operation, just as disclosed in, for example, JP-A-5-274749.
In a magnetic tape device provided with a rotation transmission path different from that used during a reproduction operation so as to enable a rapid forwarding and rewinding of a magnetic tape to be carried out, the number of parts increases by constructing the additional rotation transmission path, and the universality of the magnetic tape device is lost due to the special construction. Also, there may be some cases where a space in which parts necessary for carrying out the rapid forwarding and rewinding of a magnetic tape are installed need to be provided. Such a magnetic tape device goes against a space saving concept.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a rotational driving apparatus of a magnetic tape device capable of carrying out rapid forwarding and rewinding of a magnetic tape without specially changing the construction thereof and without causing the quality of a reproduced picture image to be deteriorated.
According to a first aspect of the invention, there is provided a rotational driving apparatus of a magnetic tape device adapted to transmit a rotation of a motor to a clutch mechanism, and transmit the rotation of the clutch mechanism to a feed reel or a take-up reel selectively via a rotation transmission path change-over gear. A first clutch mechanism and a second clutch mechanism can be provided selectively as the clutch mechanism. The first clutch mechanism being adapted to decelerate the rotation of the motor at a first reduction gear ratio, and transmit the resultant rotation to the change-over gear. The first clutch mechanism has a first shaft, a first pulley, a first clutch output gear, a first constant torque transmission member and a clutch member. The first pulley is adapted to receive the rotation of the motor and supported rotatably on the first shaft. The first clutch output gear is meshed with the change-over gear supported rotatably on the first shaft. The first constant torque transmission member is provided between the first pulley and first clutch output gear and adapted to transmit torque of lower than a predetermined level from the second pulley thereto. The clutch member is adapted to transmit the rotation of the first pulley to the first clutch output gear via the first constant torque transmission member or directly. On the other hand, the second clutch mechanism is adapted to decelerate the rotation of the motor at a second reduction ratio and transmit the resultant rotation to the change-over gear. The second clutch mechanism has a second shaft, a second pulley, a second clutch output gear, a second constant torque transmission member and a speed change clutch member. The second pulley is supported rotatably on the second shaft. The second clutch output gear is meshed with the change-over gear supported rotatably on the second shaft. The second constant torque transmission member is provided between the second pulley and second output gear and adapted to transmit torque of lower than a predetermined level from the second pulley thereto. The speed change clutch member is provided close to the second shaft and adapted to transmit the rotation of the second pulley to the second clutch output gear via the second constant torque transmission member or directly with the speed of the rotation changed.
In this rotational driving apparatus of a magnetic tape device, the first clutch mechanism and second clutch mechanism can be provided selectively as the clutch mechanism for the rotation transmission path. In the second clutch mechanism, which is different from the first clutch mechanism, the transmission of the rotation of the motor can be carried out with the speed of the rotation changed. Namely, when the speed of the rotation of the motor is changed by the second clutch mechanism at the time of, for example, carrying out rapid forwarding and rewinding of a magnetic tape, these magnetic tape handling operations can be executed at a high speed as compared with the same operations in a case where the first clutch mechanism is used. Conversely, since the speed of the rotation is changed at the time of carrying out rapid forwarding and rewinding of the magnetic tape, the reel can be rotated stably at a low speed at the time of the reproduction. Moreover, this rotational driving apparatus of a magnetic tape device is capable of using structures, other than the clutch mechanism, in common. Therefore, this rotational driving apparatus of a magnetic tape device is capable of improving a mass production efficiency thereof, and manufacturing the apparatus at a low cost.
According to a second aspect of the invention, the clutch member of the first clutch mechanism is supported on the first shaft axially movably so that the clutch member can be rotated with respect to the first shaft and engaged with and disengaged from the first pulley, the clutch member in a first pulley-disengaged state transmits the rotation of the first pulley to the first clutch output gear via the first constant torque transmission member, the clutch member in a first pulley-engaged state transmits the rotation of the first pulley to the clutch output gear directly.
In this apparatus, the clutch member is engageable with and disengageable from the first pulley. When the clutch member is disengaged from the first pulley, the rotation of the first pulley is transmitted to the first clutch output gear by the first constant torque transmission member, so that only the torque of lower than a predetermined level is transmitted. Therefore, when a sudden torque is transmitted from the motor, the transmission of the torque to the first clutch output gear can be prevented. This enables the possibility that a sudden tension, which causes the magnetic tape to be broken in some cases, be imparted to the magnetic tape to be eliminated. On the other hand, when the clutch member is engaged with the first pulley at the time of carrying out rapid forwarding and rewinding of the magnetic tape, the rotation of the motor can be wholly transmitted.
According to a third aspect of the invention, the second pulley of the second clutch mechanism has a gear portion at an outer circumferential section thereof. The second clutch mechanism has a transmission gear to which the rotation of the second pulley is transmitted via the second constant torque transmission member. The speed change clutch member of the second clutch mechanism has a speed change support shaft, a s
Funai Electric Co. Ltd.
Osha & May L.L.P.
Rodriguez Saúl
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