JPS6034127Y2 - Pinch roller holding mechanism - Google Patents

Description

[Detailed explanation of the invention] This invention is a video tape recorder (hereinafter referred to as VTR).
In this case, the pinch roller pressing mechanism that presses the pinch roller onto the capstan shaft is related to the mechanism.

In general, a VTR is configured to feed the tape at a constant speed by sandwiching the tape between a capstan shaft that rotates at a constant and accurate number of rotations and a pinch roller on a movable arm whose surface is made of rubber.

For this reason, the pinch roller is required not only to have its constituent parts made with high precision but also to be pressed with a sufficiently strong force.

Furthermore, when loading and unloading the cassette, the pinch roller must be moved to a position where it does not hit the cassette or tape.

Furthermore, in the pause state, it is necessary to quickly return to the play state, and in order to eliminate uneven rotation, it is possible to quickly return the capstan with the flywheel from stop to play state, so the capstan shaft does not need to be stopped. It is necessary to move the tape slightly away from the capstan shaft.

Conventionally, to meet these conditions, combinations of powerful electromagnets and cam links or complex cam link combination mechanisms have been used, resulting in complex mechanisms that are difficult to manufacture. There were drawbacks, such as an increase in the number of

This invention was made in order to eliminate the above-mentioned drawbacks.

An embodiment of this invention shown in FIGS. 1 to 6 will be described below.

Figures 1 and 4 are plan views showing the state in which the pinch roller is pressed against the capstan shaft and the tape is fed;
5 and 5 are plan views showing the state when the cassette is being taken in and taken out, and FIGS. 3 and 6 are plan views showing the paused state.

In these figures, 1 is a capstan shaft driven by a motor (not shown), 6 is a ring driven by a motor different from the motor that drives the capstan shaft 1, and 7 and 8 are
is a pin implanted in the ring 6, and the pin 8 is provided at a position outside the pin 7.

A cam plate 9 has cam portions 9a and 9b at one end and rotates about a fulcrum 10, and a link 12 is connected to the other end by a pin 11.

Links 14 and 15 are further rotatably connected to the link 12 by a pin 13, and the links 14, 15 and the pin 1 are connected with a pin 16 fixed to the other end of the link 14 as a fulcrum.
3 provides a toggle mechanism.

The arm 3 is connected to this toggle mechanism by a pin 17.

Reference numeral 18 denotes a spring that returns the toggle mechanism to the state shown in FIG. 5. In the state shown in FIG. 5, the link 16 and the shoulder 19b of the block 19 touch and the toggle mechanism does not return any further.

The block 19 is made of plastic, rotates around a fulcrum 20, is pulled in a fixed direction by a spring 21, and is prevented from rotating by a stopper 22.

19a is a part of the block 19, and is elastically deformed by inserting and removing the adjusting screw 23, changing the angle of the block 19 and changing the position of the fulcrum 16.

Next, the operation will be explained.

When the ring 6 rotates clockwise from the cassette loading/unloading state shown in FIG. 5, the pin 7 pushes the cam portion 9b of the cam 9 and the cam plate 9 rotates counterclockwise.

In accordance with this, the toggle mechanism is operated against the spring 18 via the link 12, and the arm 3 is rotated counterclockwise to bring the pinch roller 2 closer to the capstan shaft 1.

The pinch roller 2 maintains its position until the pin 7 gathers on the arc of the cam portion 9a of the cam 9 and the pin 8 hits the cam 9b.

This position is adjusted by inserting and removing the adjusting screw 23.

After the pin 8 hits the cam portion 9b, the pinch roller 2 is pressed against the capstan shaft 11 with a force magnified by the toggle mechanism.

At this time, since the distance from the fulcrum 10 to the pin 8 is greater than the distance from the fulcrum 10 to the pin 7, the force applied to the toggle mechanism becomes greater than before.

When the pressing force exceeds a certain level, the spring 21 expands and the block 19 escapes clockwise, so that the pressing force of the pinch roller 2 is kept constant.

Although the above description has been made using a VTR as an example, the present invention can be similarly applied to a tape recorder for recording and reproducing audio.

As mentioned above, according to this invention, the power is boosted at the final stage of the drive system and no large force is applied to the mechanical parts in the middle, resulting in fewer failures and a longer life.The stopping position of the ring may change slightly. It also has the effect of maintaining the pose state.

[Brief explanation of drawings]

1 to 6 show an embodiment of this invention, FIGS. 1 and 4 are plan views showing the state in which the pinch roller is pressed against the capstan shaft, and FIGS. 2 and 5 show the cassette. FIGS. 3 and 6 are plan views showing the pose state. In the figure, 3 is an arm, 6 is a rotation ring, 9 is a cam plate, 12, 14.15 is a link, 18, 21 is a spring, 19
is a block, and 23 is an adjustment screw. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Scope of utility model registration request] a rotating ring; a first pin embedded in the rotating ring; a second pin embedded in the rotating ring at a predetermined interval in the circumferential direction and on the inner circumferential side of the first pin; first and second pins that engage the first and second pins, respectively;
a cam plate having a cam and having one end of a first ring coupled to the other end; an arm coupled to the other end of the first ring via a second ring; and a cam plate provided on the arm. a mechanism for determining a reference interval between the pinch roller and the capstan, and the mechanism rotates the cam plate in accordance with engagement between the first pin and the first cam and the second pin and the second cam. A pinch roller holding mechanism is characterized in that the pinch roller is transmitted to the arm via the links to bring the pinch roller and capstan into close and pressure contact with each other.