JPH0378346B2 - - Google Patents

Description

Detailed Description of the Invention <Industrial Application Field> The present invention relates to a reversing drive device that can be used in a device for winding long members such as magnetic tape, recording paper, printing paper, packaging paper, rolled material, and wire. .

<Prior Art> Conventionally, various devices have been used to drive long members such as magnetic tapes, paper tapes, wires, etc. in a reversible manner. Because the diameter changes, it has been difficult to wind up a long member without slack.
In particular, if the winding direction is quickly reversed, various problems are likely to occur.

For example, in VTRs, tape recorders, etc., one reel is wound by pressing a planetary gear or pinion gear against a gear fixed to a member linked to one of the two reels, depending on the direction in which the tape is wound. The tape is driven in the take-up direction and a frictional force is applied to the other reel to wind the tape without slack. However, the gears do not always mesh smoothly, there is a time loss associated with moving the gears, and it is not only difficult to quickly reverse drive the tape to the desired position, but also makes it difficult to loosen the tape. There were cases where excessive tension was applied to the tape. A structure using rubber rollers is also known, but it cannot avoid the above-mentioned time loss and has disadvantages such as a complicated mechanism and an increase in the number of parts.

<Problems to be Solved by the Invention> In view of these shortcomings of the prior art, the main object of the present invention is to provide a device for winding a long member that can perform forward and reverse rotations without substantial time loss. The object of the present invention is to provide a reversing drive device for an elongated member such that the reversing operation can be performed.

<Means for Solving the Problems> According to the present invention, such an object is a reversing drive device that can be used for winding up a long member,
A first rotary drive unit driven by a drive source to rotate at a first speed.
a second member coupled to the first member via a first one-way clutch and to be linked to a driven object; and a second member for forcibly disengaging the first one-way clutch. and a fourth member coupled to the third member via a second one-way clutch and driven by the drive source at a second speed higher than the first speed. This is achieved by providing a reversing drive device having the following features: In particular, it is advantageous if the first one-way clutch consists of a spring clutch.

<Operation> Generally, the above-mentioned object is achieved by using a pair of such devices and disposing them so that they can rotate in forward and reverse directions using a common drive source. With such a device, when winding a tape or the like, for example, the first member is rotationally driven in a direction to engage the first one-way clutch, drives a driving object linked to the second member, and winds the tape. etc. can be rolled up. In that case, the fourth member driven at the second speed will be rotationally driven in a direction to release the second one-way clutch, and the third member will be driven at the first speed.
without damaging the engaged state of the one-way clutch.

Conversely, when this device unwinds a tape or the like, the fourth member is driven in a direction to engage the second one-way clutch, and the first one-way clutch between the first and second members is The connection by the clutch is released, and in this case, the second member linked to the driven object, such as the tape to be fed out, rotates relatively freely, allowing the tape to be fed out in a suitable manner. At this time, the second
may be driven at a relatively high speed, but the fourth member may be rotationally driven at a relatively high second speed in a direction that engages the second one-way clutch. The one-way clutch is held in the disengaged state.

Moreover, when switching between these two cases, the driving direction is simply reversed, and there is no need to move gears, rollers, etc., so the switching can be performed extremely quickly.

<Embodiments> Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 and 2 show the entire cassette tape winding structure of a TVR using a pair of reversing drive devices according to the present invention. As shown by imaginary lines in Fig. 1, reels Ra and Rb are attached to each reversing drive device A and B, respectively, and the tape T wound on these reels is wound onto the reel on the desired side. It will be.

As clearly shown in FIG. 2, a drive shaft 3 is connected to the center of frames 1a and 1b made of a pair of mutually parallel plates through bearings 2a and 2b made of synthetic resin.
A relatively large diameter gear 4 is fixed to the outer end of the drive shaft 3 protruding from the frame 1b with a screw 5. A relatively small-diameter gear 8 fixed to an output shaft 7 of a motor 6 fixed to a frame (not shown) meshes with the gear 4, and the drive shaft 3 is driven to rotate in accordance with the rotational direction of the motor 6. A gear 10 is attached to the drive shaft 3 via a pin 9 so as to be able to rotate together with the gear 10, and another gear has a similar extension 11a that engages with a boss-shaped extension 10a of the gear 10. 11 is fitted onto the drive shaft 3, and both gears 10 and 11 are driven to rotate at the same rotational speed as the drive shaft 3 rotates.

The rotational force of these two gears will be transmitted to a pair of reversing drive devices A and B, but since both of these reversing drive devices A and B have the same structure, in the following description, only one reversing drive device A and B will be transmitted. Only drive device A will be explained in detail.

As clearly shown in FIG. 3, the reversing drive device A
has a rotating shaft 13 that is rotatably supported by a pair of synthetic resin bearing members 12a and 12b like the drive shaft 3, and is prevented from coming off in the axial direction by a snap spring 14, A coupling 18 for driving the reel Ra is attached to the protruding outer end with a screw 19. A spline 19a is cut in the outer periphery of the screw 19 in the axial direction, and the coupling 18 also has a groove 1 that fits with the spline 19a.
8a is cut, so that the rotary shaft 13 is integrally driven to rotate via the screw 19. Incidentally, this coupling 18 is connected to the coupling 18 and the bearing member 1.
During rotation, a constant friction braking force is applied by a compression coil spring 20 interposed between the rotor and the rotor 2a.

A cylindrical member 15 is fitted at a position between both frames 1a and 1b of this rotating shaft 13 by a pin 17 so as to rotate integrally with the rotating shaft 13,
A gear 16 having an extension portion 16a that defines the same cylindrical outer peripheral surface as this cylindrical member 15 is attached to the rotation shaft 13.
It is fitted in such a way that it can rotate freely. This gear 1
6 meshes with the gear 11 described above.

A clutch spring 21 is fitted onto the outer periphery of a common cylindrical surface defined by the cylindrical member 15 and the extension 16a of the gear 16 so as to have a certain preload. Further, the extension portion 16a of the gear 16
A ratchet member 22 having ratchet teeth 22a on its outer peripheral surface is fitted onto the outer periphery of the clutch spring 21, and is engaged with one end of the clutch spring 21 described above. Furthermore, a gear 23 having a boss-shaped extension 23a is rotatably fitted around the outer periphery of the cylindrical member 15. The extension part 23a of this gear 23 and the gear 23
The circumferential surface formed by the undercut cut toward the inside and the circumferential surface formed on the outer periphery of the extension of the ratchet member 22 form a common cylindrical surface, and this cylinder For example, a clutch spring 24 having the same winding direction as the clutch spring 21 is wound around the outer periphery of the surface. This gear 23 meshes with the gear 10 on the drive shaft 3 side described above. Furthermore, the ratchet member 22
A locking pawl 25 that can be engaged with the ratchet teeth 22a is disposed near the outer periphery of the locking member so as to be engageable and detachable.

Next, the operation of this embodiment will be explained.

When the motor 6 is rotated in one direction, the drive shaft 3
is rotated, for example, in the direction indicated by arrow P in FIG. Then, gear 11 and gear 1
6 are in mesh with each other, the gear 16 and its extension 16a are rotationally driven in the direction indicated by the arrow P. As a result, clutch spring 2
Frictional force in the direction of tightening is added to gear 16, and gear 16
The rotational force is transmitted to the cylindrical member 15, and the coupling 18 is further rotationally driven in the direction of the arrow P via the rotating shaft 13.

At this time, the rotational force of the gear 10 is transmitted to the gear 23 at a speed ratio higher than that described above, but the gear 23 exerts a frictional force in the direction of winding and unwinding the clutch spring 24. 23 only rotates freely and does not interfere with the movement of the rotating shaft 13.

If it is desired to quickly stop this reversing drive device, it is sufficient to engage the locking pawl 25 with the ratchet tooth 22a. That is, since the engagement of the clutch spring 21 is released and the friction braking force by the torsion coil spring 20 is applied to the coupling 18,
Coupling 18 will immediately stop.

Next, when the motor 6 is rotationally driven in the opposite direction and the drive shaft 3 is rotationally driven in the direction indicated by the arrow Q, the tape is wound on the reversing drive device B side,
The reversing drive device A needs to feed out the tape without exerting excessive resistance.

In this embodiment, the gear 16 of the reversing drive device A
However, if the gear 16 is rotated at a higher speed than the coupling 18, that is, the cylindrical member 15, the clutch spring 21 will be rotated in the direction indicated by Q, which is the opposite direction to the above. This frictional force is applied, allowing the gear 16 to rotate freely, without interfering with the movement of the cylindrical member 15.

The tape that is fed out causes the gear 23 to become the gear 16.
If the clutch spring 21 is driven at a rotational speed higher than that of the clutch spring 21, a frictional force will be exerted on the clutch spring 21 in the direction of tightening it, and the movement of the gear 16 may interfere with the movement of the coupling 18. However, at this time, the gear 23 is also rotated in the same direction at a higher speed than the gear 16, which exerts a frictional force on the clutch spring 24 in the direction of tightening it. It will be rotated. This rotational driving force exerts a force in the direction of winding and unwinding the clutch spring 21. Therefore, when the coupling 18, that is, the cylindrical member 15, is rotated at a higher speed than the gear 16 by the tape being fed out, the clutch spring 21 is forcibly released by the action of the ratchet member 22, and the gear 16 is also rotated. This means that it can rotate freely. At this time, the ratchet member 2
2 is connected to the gear 23 via the clutch spring 24.
Although the clutch spring 21 is driven at a higher speed than the gear 16, the clutch spring 21 can freely slide relative to the gear 16 without causing any trouble.

In this way, even when the reversing drive A unwinds the tape, the clutch spring 21 is positively released by the ratchet member 22, so that the coupling 18 can eventually rotate freely. At this time, since the frictional force of the compression coil spring 20 is constantly applied to the coupling 18, the tape can be appropriately tensioned.

Although the present invention has been described above with reference to specific embodiments, the present invention is not limited to the above embodiments; for example,
The clutch springs 21, 24 may be other types of one-way clutches, such as a one-way clutch using a transmission means such as a roller, which transmits rotational force in only one direction. However, the clutch spring 21 must have a means for forcibly releasing the engagement.

<Effects of the Invention> As described above, according to the present invention, the elongated member can be rotated forward and backward with substantially no time loss. Moreover, this can be achieved with a relatively compact structure, and there is no need to move any special power transmission members, ensuring high durability and reliability, making it suitable for a variety of applications. It can have great effects.

[Brief explanation of drawings]

FIG. 1 comprises a reversing drive according to the invention.
FIG. 3 is a plan view showing the winding mechanism of the VTR. FIG. 2 is a partial sectional view taken along the - line in FIG. 1. FIG. 3 is an enlarged cross-sectional view of the main part of FIG. 2. 1a, 1b... Frame, 2a, 2b... Bearing member, 3... Drive shaft, 4... Gear, 5... Screw,
6...Motor, 7...Output shaft, 8...Gear, 9...
...Pin, 10...Gear, 10a...Extension part, 11
...Gear, 11a...Extension part, 12a, 12b...
... Bearing member, 13 ... Rotating shaft, 14 ... Snap spring, 15 ... Cylindrical member, 16 ... Gear, 1
6a...Extension part, 17...Pin, 18...Coupling, 18a...Groove, 19...Screw, 19a...
... Spline, 20... Compression coil spring, 21...
...clutch spring, 22... ratchet member, 22a... ratchet tooth, 23... gear, 2
3a...extension part, 24...clutch spring,
25...Latching claw.

Claims (1)

[Scope of Claims] 1. A reversing drive device that can be used to wind up a long member, comprising: a first member rotationally driven at a first speed by a drive source; a second member coupled via the first one-way clutch and to be linked to the driven object; a third member for forcibly disengaging the first one-way clutch; and the third member coupled via a second one-way clutch and driven by the drive source to the first
a fourth driven at a second speed higher than the speed of
A reversing drive device comprising: 2. The reversing drive device according to claim 1, wherein the first one-way clutch comprises a spring clutch.