JPH01113948A - Cam mechanism for magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To allow a cam gear to be a thin type and to wholly allow a set to be thin and light by providing a projecting part to a link and preventing a pin engaged to the cam channel of a slave arm from being off. CONSTITUTION:A projection 14 is revealed from a link 12, which is revolvable on the same shaft as a loading gear 8, for example, to cut a cam 8c and parallelly fit, and positioned with facing to a plain surface part 8d of the reverse surface of a cam channel 8c of the loading gear 8. When in a gap (d) between the cam gear 8 and the projection 14 of the link 12, the cam gear 8 is flexed by a load, a setting is executed so as to be abutted. In this result, the flexing is prevented and a pin 17d of a slave arm 17 is prevented from being off. Thus, the cam gear can be allowed to be the thin type.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a moving mechanism for a tape kite member of a magnetic recording/reproducing device, and particularly relates to a mechanism for moving a tape kite member of a magnetic recording/reproducing device, and in particular, a mechanism for decelerating a driving force from a motor and transmitting the driving force via a cam. Regarding the cam mechanism.

[Conventional technology]

The conventional mechanism transmits power from a motor to a cam gear through a speed reduction mechanism using a belt pulley and gears, operates a driven arm with a pin that engages in a cam groove, and operates a driven arm that has a pin that engages in a cam groove. It was operating a take guide member such as a roller.

In the case of a cam mechanism, since the load is applied to the engagement pin, the cam gear receives a moment force, which causes the cam gear to tilt.
The structure was such that the cam gear had sufficient rigidity and the engagement pin had sufficient length. Incidentally, an example of using a cam mechanism is Japanese Patent Application Laid-Open No. 61-9b65.

[Problem that the invention seeks to solve]

In the case of the above-mentioned conventional technology, when it is adopted in a small and thin mechanism compatible with recent VTR-integrated mechanisms, the cam gear becomes thinner.
As the length of engagement between the cam groove and the pin becomes shorter, and the length of the bearing becomes shorter, the cam gear itself becomes less rigid, and
As the backlash increases, the engagement pin becomes more likely to come off, and if an abnormal load is reached, the engagement pin may come off and become inoperable, a serious problem.

SUMMARY OF THE INVENTION An object of the present invention is to provide a cam mechanism for a magnetic recording/reproducing device that overcomes the drawbacks of the prior art and is compatible with a small and thin mechanism.

[Means for solving problems]

In order to achieve the above object, the present invention has a configuration of a loading gear having a cam and a link that is rotatable on the same axis and is attached in parallel, with a protrusion extending from the link. This is achieved by locating the loading gear facing the flat surface of the opposite side of the cam groove, and by setting the gap between the cam gear and the protrusion of the link so that they come into contact when the cam gear is deflected by a load.

Conversely, this can also be achieved by protruding a protrusion from the cam gear and setting it to abut against the link or chassis.

[Effect]

The aforementioned cam gear and link are positioned parallel to each other.

Since it rotates on the same axis, the distance between the protrusion from the link and the flat surface of the cam gear is maintained as long as the cam gear is not tilted. When a load is applied to the cam groove of the cam gear by the driven arm, rotational moment force is applied to the cam gear, so the cam gear tries to flex, but the cam gear comes into contact with the protrusion extending from the link, preventing the flexing, and the cam groove of the driven arm This prevents the pin from coming off.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 5 is a schematic diagram of the tape running system of the magnetic recording/reproducing apparatus according to the present invention.

In the figure, the magnetic tape is pulled out from a supply reel 2 in a cassette 1, wound around the outer periphery of a cylinder 3 at a predetermined angle, and then wound onto a take-up reel. 4 is a motor that is the power source of the mechanism, and the power of the motor 4 is transmitted through a belt 5 to a worm gear 6 and a loading gear 7.
8. These rope ink gears 7 and B include
Multi-jointed link Kanakura and tape guide on the entrance side 9. The tape guide bodies 10 on the output side are connected to each other.

The tape guide 9.10 is 1 in the unloading state.
As shown by the broken line in the figure, it is located at 117'3,
One-car loading gear 7.
When 8 rotate in opposite directions, the respective multi-joint links extend, and 1 moves in the direction of the arrow along a guide hole (not shown).

FIG. 1 is a plan view of the loading mechanism, and FIG. 2 is a sectional view thereof. In the figure, a bearing 15 is provided at the center of the loading gear 8, and the bearing 15
Links 15 and 16 are fixed to the frame 12 and rotatably connected to each other. The loading gear 8 has a cam groove 8C.
A pair of stoppers 8 are provided at a predetermined interval.
A and 8b are provided protrudingly.

The link 12 has a protrusion 12b that is connected to these stoppers aa and s.
By contacting b, the range of rotation is restricted by 70 degrees. A torsion spring 11 is wound coaxially with the bearing 16, and one end is attached to the loading gear 8, and the other end is attached to the link 1.
The link 12 is applied to the protruding portion 12a of the link 12, and the link 12 is biased. The pin 14 is fixed to the link 12 and is provided protrudingly at a position in a gap d and a plane portion tld opposite to the cam groove 8C of the loading gear 8. Followed arm 17
is attached so that the pin 17a engages with the cam groove. Although not shown, the tip of the link 16 [d tape inner body 1
0 is engaged.

FIG. 4 is a back view, in which the driven arm 17 shown in the sectional view of FIG.
It is automatically mounted around a fulcrum shaft 19 provided on the chassis 20. The driven arm 17 operates by engaging with a pin 1B of a second driven arm (not shown) which moves the audio control head 21 shown in FIG. 5VC into a predetermined position.

FIG. 5 shows a sectional view of the loading mechanism when the operating load of the driven arm 17 becomes large. The loading gear 8 receives a moment from the reaction force FQ received from the driven arm 17,
The angle of inclination with the bearing 15, and.

Deflect. However, since the loading gear 8 comes into contact with the link pin 14, which is fixed to the link 12 and provided in a protruding manner, when the loading gear 8 is deflected by the gap δ, the deflection is prevented there, so that the pin 17a of the driven arm 17 does not come off. .

FIG. 6 shows a cross-sectional view of a loading mechanism that is on the verge of death when the conventional link 12 is not provided with a protrusion and the operating load of the driven arm 17 becomes large. The loading gear 8 is deflected by the reaction force from the driven arm 17, and the pin 17a of the driven arm 17 comes off by the amount of deflection δ. As a result, the pins come off, making it impossible to operate and causing temperatures to rise.

FIG. 7 shows an example in which a protrusion is provided from the loading gear 8. In this case, when the loading gear 8 is deflected by the reaction force of the driven arm 17, the cam gear protrusion 8e comes into contact with the link 12 to prevent the loading gear 8 from deflecting and prevent the pin 17a of the driven arm 17 from coming off.

If the cam gear protrusion 8e is provided in a half-ring shape at an appropriate position Ii within the rotational range of the link 12, it can even withstand some misalignment due to load.

It can have a deflection prevention function.

To prevent an engagement pin from coming off from a cam groove without increasing the number of parts or increasing costs, whether the protrusion is taken out from the link or the cam gear. Can be done.

〔Effect of the invention〕

According to the invention, by providing a simple protrusion.

Since it is possible to prevent the pin that engages with the cam groove of the driven arm from coming off, the cam gear can be made thinner, and there is no need for highly rigid materials such as tie cast, and the material itself has low rigidity such as plastic. Is the entire set available? !
! It has the effect of being smaller in size and lighter in weight. Furthermore, serious defects such as pin dislodgement can be prevented, and highly reliable and stable operation can be achieved.

[Brief explanation of the drawing]

Figure 1 is a plan view of a loading mechanism according to an embodiment of the present invention, Figure 2 is a sectional view thereof, Figure 5 is a schematic diagram of a tape running system, and Figure 4 is the back side of the mechanism. FIG. 5 is a cross-sectional view of the no-loading mechanism when the cam gear is bent in the case of implementing the present invention, FIG. 6 is a cross-sectional view showing the state in which the cam gear is bent and the engagement pin is disengaged in the conventional case, and FIG.
The figure is a sectional view showing a case where the protrusion is taken out from the cam gear. 8... Loading gear, 8c... Cam groove. 12... Link, 14... Link pin (protrusion). 17... Driven arm, 17a... Driven arm pin, 8e... Cam gear protrusion, 13... Bearing. 11... Torsion spring. Representative Patent Attorney Masaru Ogawa:,,・:,j,1.
i 1st study Z side 2b ゛bu..., Noo 3 Ward 4- Figure 5th 86 Figure 77

Claims (1)

[Claims] 1. A cam gear to which the power of the motor is transmitted via a reduction mechanism, a link parallel to the cam gear coaxially with the cam gear and biased by a spring so as to be rotatable, and a cam groove of the cam gear. In a magnetic recording and reproducing device having a driven arm having an engaging pin and a transmission mechanism that engages with the driven arm and operates a tape guide, the cam gear is provided with a smooth flat surface on a surface opposite to the cam groove; , a protrusion is provided from the link so that it will come into contact with the flat surface and prevent the engagement pin from coming off when the cam gear bends due to an excessive load on the driven arm and the engagement pin of the driven arm attempts to come off. The cam mechanism of the magnetic recording and reproducing device is a feature. 2. A projection is provided on the surface opposite to the cam groove of the cam gear, and a flat portion is provided opposite to the projection so as to come into contact when the cam gear is bent due to an excessive load on the driven arm and the engagement pin of the driven arm is about to come off. A cam mechanism for a magnetic recording/reproducing device according to claim 1, wherein the cam mechanism is provided in a link or a chassis.