JPH0348749Y2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Field of Industrial Application The present invention relates to a reel stand assembly mechanism that makes it possible to apply back tension using a one-way clutch of a tape recorder.

(b) Conventional technology The first reel stand assembly mechanism that uses a one-way clutch to provide back tension has been developed.
There is a conventional mechanism as shown in FIG. In this conventional mechanism, a thrust bearing 3 is disposed at the lowest part of a shaft 2 that is erected on a chassis 1, and a tension pulley 4 is rotatably disposed on the thrust bearing 3. On the other hand, the reel stand 5 skewers a review gear 6, which has felts 6a, 6a on both sides, a spring coil receiver 7, a spring coil 8, and a rewind gear 9, on a cylindrical portion 5a integrally molded below. After inserting the ring 10 constituting the outer ring of the one-way clutch in order, the three rollers 11, 11, 11 are inserted into the notch 10 inside the ring.
a, 10a, and 10a, the clutch pulley 12 constituting the inner ring of the one-way clutch is press-fitted into the tip of the cylindrical portion 5a to prevent it from coming off. It should be noted that, as a matter of course, the review gear 6 is rotatably fitted into the cylindrical portion 5a, but the rewind gear 9 is fixed. The reel stand 5 assembled in this manner is inserted into the shaft 2, and the outer periphery of the ring 10 and the inner periphery of the tension pulley are engaged. Further, a coil spring 1 is attached to a cylindrical portion 5b formed above the reel stand 5.
3 and the spindle 14 are fitted, a cap 15 is fitted between the shaft 2 and the cylindrical part 5b, and finally an E washer 16 is fitted to the tip of the shaft 2. In this state, a brake band 17 is arranged around the outer periphery of the back tension pulley 4. One end of this brake band 17 is fixed, and the other end is fixed to a back tension lever 18, and the brake band 17 is tightened according to the tape tension detected by a back tension pin 19. .

FIG. 2 is a sectional view taken along line A-A' in FIG. 1, and clearly shows the shape of the one-way clutch. As is clear from this figure, the notches 10a, 10a, 10 of the ring 10 that accommodates the rollers 11, 11, 11.
a is deeply formed in the counterclockwise direction,
When the brake band 17 applies braking to the tension pulley 4, which rotates clockwise as the tape is fed out, the rollers 11, 11, 11 move into the notch 1.
0a, 10a, and 10a in a clockwise direction, that is, in the direction of shallower notches. roller 11,1
1 and 11 move in a shallower direction, the amount of braking applied to the reel stand 5 increases.

Therefore, the shape of the notches 10a, 10a, 10a and the outer shape of the clutch pulley 12 will have a subtle effect on the braking force. In spite of this, the clutch pulley 12 functions as a retainer and is press-fitted into the cylindrical portion 5a, causing deformation due to the press-fitting.

In addition, in such a conventional mechanism, the roller 1 is
The clutch pulley 12 must be press-fitted with the rollers 1, 11, 11 stationary in the notches 10a, 10a, 10a.
Great care had to be taken not to move beyond 0a, 10a, and 10a. As a result, workability deteriorated.

(c) Purpose of the invention Therefore, the present invention aims to propose a reel stand assembly mechanism that has excellent assembly workability and less deformation.

(d) Structure of the invention The invention comprises a tension pulley that rotatably fits into the lower part of the shaft mounted on the chassis and integrally molds the inner ring of the one-way clutch above, and the outer ring of the one-way clutch. ring and
a reel stand that rotatably fits on the upper part of the shaft and engages the ring downward; and a back that applies braking to the tension pulley in response to tape tension fed out from a tape reel fitted to the reel stand. A tension mechanism is provided.

(e) Example In this example, the present invention is applied to a supply reel stand of a video tape recorder that fits into a supply reel in a cassette, and the torque and rotational speed of this reel stand are controlled by a motor. Since this is a type of reel stand that selectively connects the idler, it has a simple structure that does not include a slip mechanism with a felt like in the conventional example.

This embodiment will be described below with reference to FIG. 3 and FIG. 4 showing a cross section taken along line B-B' in FIG. In this embodiment, as shown in FIG. 3, a thrust bearing 3 is arranged at the lower end of a shaft 2 which is set up on a chassis 1, a tension pulley 4 is fitted into the lower part of the shaft 2, and a reel stand is installed at the upper part. 5 is fitted and inserted, and a cap 15 is attached to the upper end of the shaft 2. The tension pulley 4 has an outer ring portion 4a around which the brake band 17 is attached, an inner ring portion 4b forming a one-way clutch, and a locking rib 4c into which the roller regulating member 20 is fitted. . The ring 10 that constitutes a one-way clutch together with the inner ring portion 4b has notches 10 at three locations on the inner circumference.
a, 10a, 10a, and the notches are formed shallowly in the counterclockwise direction, contrary to the conventional example. Moreover, a notch 10b formed on the outer periphery of this ring 10
Engagement ribs 5a, 5a, 5a formed below the reel stand 5 are engaged with the three locations, and the reel stand 5 and the ring 10 rotate integrally.

Therefore, when the back tension lever 18 rotates clockwise due to a decrease in tape tension, the brake band 17 brakes the tension pulley 4, and the inner ring portion 4b rotates counterclockwise relative to the ring 10. It can be rotated in the direction. This relative rotation causes the rollers 11, 11, 11 in the notch to
is moved in the shallow direction of the notches 10a, 10a, 10a, and the amount of braking applied to the reel stand 5 is controlled according to the amount of this movement.

In assembling the mechanism of this embodiment, first, the tension pulley 4 is inserted into the shaft 2.
Subsequently, the ring 10 is fitted into the inner ring portion 4b, and the notches 10a, 10a, 10a are
The rollers 11, 11, 11 are inserted therein, and the roller regulating member 20 is fixed to the outer periphery of the locking rib 4c. Subsequently, the notch 10a of the ring 10
The reel stand 5 is fitted into the shaft so that the engaging rib 5a of the reel stand 5 is fitted into the shaft.
Thereafter, with the coil spring 13 and spindle 14 fitted into the cylindrical portion 5b on the reel stand 5, the cap 15 is fitted and fixed inside the cylindrical portion 5b, and the E washer 16 is attached to the shaft 2. Assembly is easy.

In this embodiment, the ring side is notched and the roller is fitted therein, but it goes without saying that the inner surface of the ring may be formed into a cylindrical shape and a notch may be formed in the inner ring portion.

(c) Effects of the invention Therefore, according to the invention, the inner peripheral surface of the one-way clutch is formed inside the tension pulley that is directly fitted to the shaft, so that the inner peripheral surface of the clutch is not distorted. The stability of the movement is increased and smooth tension control is possible.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway sectional view of a conventional mechanism, Fig. 2 is a sectional view taken along line A-A' in the same figure, Fig. 3 is a vertical sectional view of an embodiment of the mechanism of the present invention, and Fig. 4 is a cross-sectional view of the same figure. A BB' sectional view is shown. Explanation of the main drawing numbers: 1... Chassis, 2... Shaft, 4... Tension pulley, 5... Reel stand, 10... Ring, 17... Brake band.

Claims (1)

[Scope of utility model registration request] A tension pulley that rotatably fits into the lower part of the shaft installed on the chassis and integrally molds the inner ring of the one-way clutch above, a ring that forms the outer ring of the one-way clutch, and a ring that rotatably fits into the upper part of the shaft. a supply reel stand that fits into the supply reel stand and engages the ring downward; and a back tension applying mechanism that applies braking to the tension pulley according to the tape tension fed out from the tape reel that fits into the supply reel stand. A reel stand assembly mechanism consisting of each.