JPH04301252A - Driving force transmitting device - Google Patents

Abstract

PURPOSE:To constitute a driving force transmitting device to secure stable operation even if some deformation is caused in a rotating arm in the driving force transmitting device in which a first gear engaging with a driving gear and being driven and rotated by the same is installed on the rotating arm held freely rotatably by the shaft of the driving gear to be driven and rotated by a driving source, and a driven body which the gear engages with is selected by rotating the arm according to the rotating direction of the driving gear. CONSTITUTION:At least, a part of the engaging hole 6 of the rotating arm 5 to engage with the shaft 3 of the driving gear 1 is made a slot long along the longitudinal direction of the above mentioned rotating arm 5.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a driving force transmission system used when selectively driving two close driven bodies such as a supply reel and a take-up reel in a magnetic recording/reproducing apparatus by a single driving source. It is related to the device.

0002

2. Description of the Related Art Conventionally, as a driving force transmission device that automatically selects and drives a supply reel and a take-up reel using a single drive source according to their rotational directions, there is a device shown in FIGS. 3 to 5. It is considered.

In FIGS. 3 to 5, reference numeral 1 denotes a drive gear rotatably held on a shaft 3 embedded in a substrate 2, and is rotationally driven by a gear 4 driven by a motor (not shown).

Reference numeral 5 denotes a rotating arm supported by the shaft 3 through an engagement hole 6 so as to be rotatable independently of the drive gear 1.

A first gear 8 is rotatably held on a shaft 9 provided on the rotating arm 5, and its outer periphery is engaged with the drive gear 1. Also, this first gear 8 is attached to the felt 8 by the urging force of the spring 7.
They are frictionally engaged via a.

In the above configuration, when the drive gear 1 rotates in the direction of arrow A, a force is applied to the first gear 8 to rotate in the direction of arrow B, causing frictional engagement with the first gear 8. The rotating arm 5 rotates in the direction of arrow C, and the first gear 8 engages with the second gear 10 which drives the supply reel.

After the first gear 8 and the second gear 10 are engaged, rotation of the rotating arm 5 is prevented, so the first gear 8 overcomes the frictional engagement and moves in the direction of arrow B. It starts rotating and drives the supply reel via the second gear 10.

Further, when the driving gear 1 rotates in the direction opposite to the direction of arrow A, the rotating arm 5 rotates in the direction opposite to the direction of arrow B, and the first gear 8 rotates as shown by the dotted line in FIG. engages with the third gear 11 that drives the take-up reel to drive the take-up reel. In this way, either the supply reel or the take-up reel can be selectively driven automatically depending on the rotational direction of the drive gear 1.

In order to stabilize the operation when driving the reel, the tip 5a of the rotating arm 5 is configured to slide on a fixed base plate 12, and as shown in FIG. A position regulating member 13 is provided on the substrate 12, and when the first gear 8 and the second gear 10 or the third gear 11 are engaged, the tip of the rotating arm 5 is positioned between the regulating member 13 and the fixed substrate 12. It is configured so that it is held between the two.

0010

However, in the conventional structure described above, when the rotating arm 5 is made of a material with low mechanical strength such as resin, deformation as shown by the dotted line in FIG. 4 occurs during use. Engagement with the position regulating member 13 may become impossible.

The present invention is constructed so that stable operation can be performed even if the rotating arm 5 is slightly deformed.

0012

[Means for Solving the Problems] A driving force transmission device of the present invention is rotatably held on the shaft of a driving gear rotationally driven by a driving source, and rotates by frictional engagement as the driving gear rotates. A rotating rotating arm is provided with a first gear that is engaged with and rotationally driven by the driving gear, and the rotating arm is rotated in accordance with the rotational direction of the driving gear to rotate the first gear. In the driving force transmission device for selecting a driven body to be engaged with, a part of the engagement hole of the rotating arm that engages with the shaft is formed into a long hole that is elongated in the longitudinal direction of the rotating arm.

[0013]

[Function] According to this configuration, even if the rotating arm is slightly deformed, a part of the engagement hole that engages with the shaft is an elongated hole that is long in the longitudinal direction of the rotating arm, so the shaft The position of the tip of the rotary arm can be kept unchanged without applying excessive force between the rotary arm and the rotary arm.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a side sectional view of a driving force transmission device according to the present invention, in which the same components as those of the conventional example described above are given the same reference numerals.

The difference from the conventional example is that, as shown in FIG. It is located in a point configured in an elliptical shape that is long in the direction.

According to this configuration, even if the rotating arm 5 is deformed as shown by the dotted line in FIG. Therefore, as shown in Fig. 2, even if the position of the tip of the rotating arm 5 is changed, no unreasonable force is generated between the engagement hole 6 and the shaft 3, and stable operation can be expected. be.

[0018]

[Effects of the Invention] As described above, according to the present invention, stable operation can be expected even if the rotating arm is slightly deformed, and therefore the rotating arm does not need to have an unnecessarily strong structure. It is good, and accuracy is not strictly required.

[Brief explanation of the drawing]

[Fig. 1] A side sectional view of the main part showing an embodiment of the driving force transmission device of the present invention.

[Figure 2] Side cross-sectional view of main parts of the same embodiment

[Fig. 3] A plan view of essential parts showing an example of a conventional driving force transmission device

[Figure 4] Side sectional view of the main parts of the device

[Figure 5] Perspective view of the main parts

[Explanation of symbols]

1 Drive gear 3 axis 5 Rotating arm 6 Engagement hole 8 First gear

Claims (1)

[Claims] Claims: 1. A rotating arm rotatably held on the shaft of a drive gear rotationally driven by a drive source; a first gear engaged with and rotationally driven by the drive gear;
When there is no predetermined rotation load on the rotation arm, the rotation arm rotates together with the drive gear, and when there is a rotation load greater than a predetermined amount, the first gear rotates together with the drive gear. In the driving force transmission device, the rotating arm is rotated according to the rotational direction of the driving gear to select a driven body with which the first gear engages. A driving force transmission device in which at least a part of the engagement hole of the rotating arm is a long hole extending in the longitudinal direction of the rotating arm.