JPH0481819B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a pinch roller pressure contact mechanism for magnetic recording and reproducing devices such as VTRs and tape recorders.

The present inventor has already proposed a mechanism for mechanically pulling out the tape from the cassette with a pinch roller and pressing the pinch roller against the capstan shaft in a magnetic recording/reproducing device such as a VTR. However, first, let's talk about this mechanism in Part 3.
This will be explained based on the diagram and FIG.

In Figure 3, 1 is the main lever, arrow a
It is possible to move linearly in the direction. A pinch roller arm 2 is rotatably attached to the fixed shaft 3 and rotatably supports the pinch roller 4. In response to the movement of the main lever 1 in the direction a, the pinch roller 4 is rotated in a known manner in response to the movement of the main lever 1 in the direction a by a combination of a rotary lever 7 and the like that can be rotated around the main lever 7, and the pinch roller 4 is rotated in a known manner. 8 and near the capstan shaft 9. The pinch roller arm 2 is rotatably connected to one end of a first link 11 via a connecting pin 10, and the other end of the first link 11 is connected to a second link 13 via a moving pin 12. It is rotatably connected to one end of the. The other end of the second link 13 is rotatably connected to the intermediate portion of the press lever 15 via a connecting pin 14. One end of the pressing lever 15 is rotatably supported by a fixed shaft 16, and a guide elongated hole 17 is formed in the other end. This guide slot 27 has a fixed regulation pin 28.
is loosely fitted. Furthermore, a spring 19 that applies a biasing force in the direction of arrow b is attached to the other end of the pressure contact lever 15.
are connected (one end of the spring 19 is connected to a fixing member, not shown). Further, the main lever 1 is provided with a rectangular notch 20, and one side edge 20a of this notch 20 can be engaged with the movable pin 12.

In the above configuration, immediately after the pinch roller 4 and tape 8 are brought near the capstan shaft 9, one side edge 20a of the notch 20 formed in the main lever 1 just contacts the movable pin 12. state. In this state, when the main lever 1 is moved in the direction of arrow a, one side edge 20a of the notch 20
The movable pin 12 that has come into contact with the moving pin 12 also moves in the same way, causing both links 11 and 13 to open and expand.As a result, the pinch roller arm 2 rotates slightly in the direction of the capstan shaft 9, and the pinch roller 4 moves toward the capstan shaft 9. Contact. While the pinch roller arm 2 can rotate in this manner, the pressure contact lever 15, which is pulled by the spring 19, does not rotate, and therefore the connecting pin 14 does not rotate.
The position of is held constant. However, after the pinch roller 4 contacts the capstan shaft 9,
Even if the moving pin 12 is moved by further movement of the main lever 1 in the direction of arrow a and both links 20 and 23 are expanded, the pinch roller arm 2 can no longer be rotated. The expansion is absorbed by the rotation of the pressing lever 15 in the direction of arrow d against the biasing force of the spring 19 in the direction b. As a result, the biasing force of the stretched spring 19 is applied to the pressing lever 15, both links 11, 13,
and transmitted via the pinch roller arm 2,
The pinch roller 4 is pressed against the capstan shaft 9,
It is capable of generating the required tape driving force.

However, in general, when rewinding and playing, the tension band must be released to lighten the load on the supply reel stand, so the main lever 1 is moved to the tension post or tension band position. ing. Therefore,
The position of the main lever 1 is different during recording and playback and during rewind playback, and as a result, in the above mechanism, as shown in FIG. This results in a large shift to the position shown during rewind playback. This means that
This results in a large difference in the amount of extension of the spring 19, resulting in a large difference in pinch pressure between recording and playback and rewinding playback, which can cause tape slippage, or conversely, too much load is applied to the capstan shaft 9, causing it to become deformed. This may cause

OBJECTS OF THE INVENTION The present invention solves the above-mentioned problems, and an object of the present invention is to provide a pinch roller pressure contact mechanism for a magnetic recording/reproducing device in which the pinch pressure does not change much during recording/reproducing and rewinding/reproducing. It is something to do.

Composition of the Invention In order to achieve the above object, a pinch roller pressure contact mechanism of a magnetic recording/reproducing device according to the present invention includes a rotatable pinch roller arm to which a rotatably attached pinch roller and a linearly movable main lever are provided. a first link rotatably connected to the pinch roller arm; a second link rotatably connected to the first link via a movable pin;
The main lever includes a rotatable pressing lever rotatably connected to the second link and a spring that biases the pinch roller in a direction to press the pinch roller against the capstan shaft via both links. It has a notch that engages and moves the movable pin at one side edge by linear movement in the direction to spread both links and press the pinch roller against the capstan shaft, and one side edge of this notch is stepped. When the notch is in the recording/reproducing position, the moving pin is located below the step, and when the notch is in the rewinding/playing position, the moving pin is located above the step. , the position of the stepped portion is set.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. Note that since the present invention is based on the mechanism shown in FIG. 3, only the parts that are different from this will be explained here, and the explanation of other parts will be omitted.

In Figures 1 and 2, main lever 1
(see Fig. 3) has a notch 20', and this notch 20' has a step S at one side edge 20'a.
have. When the pinch roller is in pressure contact with the capstan shaft, the position of the connecting pin 10 does not change, so the movable pin 12 moves along an arcuate path centered on the connecting pin 10. Therefore, the step S
is the notch 2 that the movable pin 12 occupies during recording and reproduction.
It is preferable that the movable pin 12 be along an arc having a radius r and centered at a height h from the bottom surface of the movable pin 12.

In the above configuration, when the notch 20' is displaced from the recording/reproducing position shown by the solid line in FIG. , the absolute position of the movable pin 12 does not change much, and the amount of change in pinch pressure can be suppressed to a minimum.

Note that the position and shape of the stepped portion S are not limited to those shown in the drawings, and the position and shape of the stepped portion S are not limited to those shown in the drawings.
It is sufficient to set it so that it is located below the stepped portion S and positioned above the stepped portion S during rewinding.

Effects of the Invention As described above, in the pinch roller pressure contact mechanism of the magnetic recording and reproducing device of the present invention, during recording and reproducing, the movable pin is located below the stepped portion provided on one side edge of the notch, and the movable pin is Since the movable pin is positioned above the stepped portion during playback, the amount of change in pinch pressure in both operation modes can be minimized and stable tape running can be realized at all times.

[Brief explanation of drawings]

Fig. 1 is a plan view showing the main parts of an embodiment of the present invention, Fig. 2 is a plan view showing the operating principle of the embodiment, and Fig. 3 is a pinch roller of a magnetic recording/reproducing device which is the basis of the present invention. FIG. 4 is a schematic plan view showing the pressure contact mechanism, and FIG. 4 is a plan view showing the principle of operation of the same mechanism. 1... Main lever, 2... Pinch roller arm, 4... Pinch roller, 9... Capstan shaft, 11... First link, 12... Moving pin,
13... Second link, 15... Pressing lever,
19... Spring, 20'... Notch, 20'a... One side edge of the notch, S... Step portion.

Claims (1)

[Claims] 1. A rotatable pinch roller arm to which a pinch roller is rotatably attached, a linearly movable main lever, a first link rotatably connected to the pinch roller arm, and a lever that moves to the first link. A second link rotatably connected via a pin, a rotatable pressing lever rotatably connected to the second link, and a pinch roller connected to the capstan via the pressing lever and both links. The main lever is provided with a spring biased in the direction of pressure contact with the shaft, and when the main lever moves linearly in one direction, it engages and moves the movable pin at one side edge to spread both links, thereby causing the pinch roller to move. has a notch that presses the capstan shaft into contact with the capstan shaft, one side edge of this notch has a step, and when the notch is in the recording/playback position, the movable pin is located below the step, and the notch A pinch roller pressure contact mechanism for a magnetic recording/reproducing device, wherein the position of a stepped portion is set so that a movable pin is located above the stepped portion when the is in a rewinding and reproducing position.