JPS597131B2 - electromagnetic locking device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION 35. The present invention relates to a device for switching channels by vertically moving a magnetic head of a magnetic tape recording/reproducing device having a plurality of channels.

In conventional magnetic head devices of this type, a rotatable pawl attached to an electromagnetic mechanism is hooked onto a protrusion provided on a flywheel to derive driving force for switching magnetic tracks.

However, with this type of device, depending on the length of the sensing conductor for detecting the end of the tape and the length of time the channel switching push button is pressed, channels may not be switched or two channels may not be switched unexpectedly in one operation. There were many malfunctions, such as switching channels twice or three times.

In addition, the sound of impact between the protrusion provided on the flywheel and the pawl for channel switching was loud, and the sound of the plunger's operation was too loud to be suitable for indoor use. In particular, the present invention solves the problem of malfunction by extracting driving force from the outer peripheral surface of the capstan through an idler wheel, and by performing channel switching operation only when the electromagnetic device changes from an energized state to a de-energized state. It was solved by At the same time, impact noise is also minimized due to the use of idle wheels, and power consumption is also minimized because less power is required for operation. Furthermore, it is an object of the present invention to provide an apparatus which has a reduced number of component parts and is excellent in mass production and economy. Embodiments of the invention will now be described in detail with reference to the drawings.

In FIG. 1, a magnetic tape 1 is driven through a tape guide 2, between a capstan 3 and an idler (not shown) pressing the capstan 3, and is driven to a magnetic head 5.
drive in contact with. The magnetic head 5 is attached to a head holder 6.
It is held between the two. The head holder 6 is supported so as to be vertically slidable via a support shaft 7 for vertically moving the head. The guide pin 9 is for preventing the head holder 6 from rotating. The head vertical pin 10, which is installed on the head holder 6 and serves as an abutting member, has a head height regulating spring 13 on a support shaft 7 for vertically moving the head, and the head holder 6 is connected to a stepped cam 11 for vertically moving the head. It is in contact with and is constantly pressed. The step cam 11 is provided with an idler wheel 1 integrated with the step cam 11 to prevent channel switching from becoming unstable due to changes in the horizontal reference position or inclination due to external pressure during operation.
The idler wheel position adjustment spring 15 is attached to the idler wheel support shaft 14, which is a second support shaft which rotatably supports the idler wheel 2, and is pressed upward to regulate the idler wheel position. Further, the step cam 11 has a sliding plane opposite to the step cam 11, and a position that opposes the pressure from the head up/down pin 10, that is, an idler spindle 14.
A step cam regulating pin 17 is fixed on a straight line parallel to the axial direction of the head and connecting the head up and down pins 10 through a housing 16 which serves as a chassis that protects the head up and down mechanism. Inclination due to pressure contact of the pin 10 is restricted. The idler wheel 12 therefore rotates step by step to ensure that a predetermined channel position is selected. When the idler wheel 12 is installed coaxially with the step cam 11 and is supported on the idler wheel support shaft 14, it is necessary to remove the bearing part when mass producing the idler wheel 12. Since this gradient cannot be reduced below a certain value, it is meaningless to try to reduce the inclination by making the bearing portions of the step cam 11 and the idler wheel 12 longer. Therefore, the step cam regulating pin 17 is provided in order to restrict the inclination of the step cam 11 and further reduce the force applied to the idler wheel support shaft 14 and the bearing portion supported by the idler wheel support shaft 14. has an important role in Hereinafter, in FIGS. 2 and 3, the same symbols represent the same members.

Next, in FIGS. 2 and 3, the idler wheel 1 of the first embodiment is shown.
The second operation will be explained.

The electromagnetic device 18 is affixed to the main body or chassis 40 (shown in the third figure).

An actuator 19 attracted to the electromagnetic device 18 has one end rotatably held by a portion of the electromagnetic device 18 . The actuator 19 is always elastically repelled by the actuator spring 20 in a direction away from the electromagnetic device 18. The idler wheel lever 21, which is a rotating lever, has its center connected to the main body or the chassis 4.
It is rotatably supported by a lever support shaft 22, which is a first support shaft, which is erected at 0. Idle wheel support shaft 14 of the idler wheel 12
is installed on the idler wheel lever 21. The stage cam 11 is
Number of channels used, for example equal to 4 channels, 9
It is composed of four steps with a 0 degree opening angle and different heights. At the right end of the opening of the idler lever 21 is a first locking mechanism 23 that locks the actuator 19 when the electromagnetic device is in a de-energized state.
- The left end of the opening of the A1 idler wheel lever 21 is provided with an idler lever 21 when the electromagnetic device 18 is turned into an excited state.
A second locking mechanism 23- that continuously locks the actuator 19
B1 First locking mechanism 23-A and second locking mechanism 23-B
A lock release mechanism 23-C, which has a concave portion located in the middle of the lock release mechanism 23-C, is provided for unlocking the actuator 19 when the electromagnetic device 18 is subsequently changed to a non-excited state.
Furthermore, an idler wheel pressure contact spring 24 is attached to the idler wheel lever 21.
is applied to the idler wheel 12, and the drive wheel 25, which constitutes a part of the capstan 3, is resiliently repelled in the direction in which it comes into pressure contact with the idler wheel 12. The outer periphery of the driving wheel 25 or the idler wheel 12 is coated with, for example, rubber in order to increase friction. The drive wheel 25 is coaxial with the flywheel 26. While the electromagnetic device 18 is not energized, the actuator 19 is separated from the electromagnetic device 18 by the elastic force of the actuator spring 20, so that the idler wheel lever 21
The driving wheel 25 and the idler wheel 12 remain separated from each other. When the electromagnetic device 18 is energized, the actuator 19 is attracted to the electromagnetic device 18 against the elastic force of the actuator spring 20, and the free end of the actuator 19 is connected to the first chain of the idler lever 21. It separates from the lock machine 23-A and is attracted to the electromagnetic device 18. Here, the actuator 19 locks the second locking mechanism 23-B of the idler wheel lever 21, and the idler lever 21 is further rotated by the idler wheel pressure contact spring 24, and the idler wheel 12 is further rotated by the idler wheel pressure contact spring 24. This prevents the drive wheel 25 from coming into pressure contact with the drive wheel 25 forming a part of the capstan 3. When the electromagnetic device 18 is de-energized, the actuator 19
is detached from the second locking mechanism 23-B, the actuator 19 is fitted into the lock release mechanism 23-C, and the idler wheel 12 is disengaged from the drive wheel 2.
5. The diameter change due to rotation of the pressed idler wheel 12 is smooth as shown in FIG. The idler lever 21 performs a see-saw movement around the rotary lever support shaft 22 as shown in FIG. 4 with the actuator 19 fitted into the unlocking mechanism 23-C. When the distance between the centers of the drive wheel 25 and the idler wheel 12 reaches the maximum, the actuator 19 is ejected from the lock release mechanism 23-C, and the elastic force of the actuator spring 20 causes the actuator 19 to return to the first lock mechanism. 23-A to suppress the operation of the idler wheel lever 21. As described above, the idler wheel 12 repeats the above-described operation every time the energization is stopped. Other symbols that are the same as those in FIG. 1 represent the same members and have the same functions and effects. Therefore, each time the electromagnetic device 18 is energized and energized, and subsequently de-energized, the magnetic head 5
is stepped one step at a time. As explained above,
In the present invention, the torque of the motor is reduced and increased by the flywheel 26 and the capstan 3, and since the idler wheel 12 rotates on an axis, there is no sliding friction, so the operation is accurate. It is highly reliable and effective.

In addition, the number of parts is small, the shape is simple, and mass production is easy. In particular, the channel switching operation is performed only when a current flows through the electromagnetic device 18 once and changes to the energized state and then to the de-energized state. Irrespective of this, the operation of switching one channel of the l signal is carried out reliably, and there is no malfunction caused by the timing of pressing the push button. Note that since the main power for magnetic track switching is taken out from the capstan 3, a small capacity and small output are sufficient. In addition, in the main unit, the necessary energy is obtained through the rotation of the drive wheel 25, so that no impact noise is generated and the operation is smooth.
Furthermore, since the idler wheel 12 and the drive wheel 25 move together regardless of the rotation angle of the cab stan 3, there is no need to consider the timing of operation, so there is no malfunction caused by the timing of power transmission. Furthermore, there is no need to rely on the inertia of the flywheel, and therefore there is no need to increase the moment of inertia for any purpose other than to reduce wow and flutter during magnetic tape running.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the main parts of magnetic track switching, FIGS. 2 and 3 are a plan view and side view of a first magnetic trunk switching device according to the present invention, and FIG. 4 is a graph regarding a quadrilateral idler. 1...magnetic tape, 2...tape guide, 3...capstan, 5...magnetic head, 6...head 5 head holding Ingredients, 7...
... Support shaft for moving the head up and down, 10... Pin for moving the head up and down, 11... Step cam, 12...
Idler wheel, 16...Housing, 17...
・Step cam regulation pin, 18... Electromagnetic device, 19.
... Actuator, 21 ... Idler wheel lever,
25... Drive wheel, 260... Flywheel, 40... Body or chassis.

Claims (1)

[Claims] 1. A support lever for an idler wheel rotatably supported by a first support shaft provided on the main body, and a second support shaft installed at the free end of the support lever. An idler wheel, a cam portion provided on the outer periphery so that the diameter from the rotation center of the idler wheel to the capstan pressure contact surface changes periodically with rotation, and a cam portion provided on the outer periphery, and the cam portion driven by a magnetic tape. a first spring for elastically repelling the support lever for the idler wheel in a direction in which it comes into pressure contact with the capstan for the drive; an actuator rotatably supported by the main body so as to be able to move toward and away from the open end of the magnetic path; a second spring that elastically repels the actuator in a direction away from the open end of the magnetic path; and the support lever described above. When the opening provided at the free end of the opening and the aforementioned actuator are spring-backed by the second spring, the actuator contacts the first locking portion provided on the inner wall of one side of the opening. a first locking device that locks the support lever against the elastic force of the first spring to hold the idler wheel apart from the capstan; When the above-mentioned excitation coil is energized through the magnetic path and the above-mentioned actuator is attracted and rotated to the open end of the magnetic path, it comes into contact with the second lock part provided on the other inner wall of the opening, a second locking device that locks the support lever against the elastic force of the first spring to maintain the separated state between the idler wheel and the capstan;
When the excitation coil is de-energized due to disappearance of the end mark detection signal, the support lever is unlocked by the actuator, and when the actuator enters the deep part of the opening, the first spring is activated. A mechanism in which the support lever rotates due to elastic force and presses the cam portion of the idler wheel against the capstan to receive power transmission, and the idler wheel rotates by a predetermined angle,
The supporting lever for the idler wheel reciprocates once and is locked again in the first locking part of the opening, and then by further rotation of the idler wheel at a slight angle,
The magnetic track is switched by moving the magnetic head one step through a mechanism in which the idler wheel is separated from the capstan and stopped, and a head vertical movement pin that contacts the cam surface of the stepped cam that rotates in synchronization with the idler wheel. An electromagnetic locking device characterized by comprising a mechanism.