GB2086677A - Clutch mechanism for a pushbutton tuner - Google Patents

Abstract

A clutch mechanism for a pushbutton tuner wherein a clutch lever 3 and a spring 5 for pressing the clutch lever in a direction for operating the clutch mechanism are mounted on a support shaft 4 on which components of the clutch mechanism are mounted and an end portion of the spring rests on a plate member 16 fitted on the support shaft and engages with an engaging means 16 formed on the plate member concentrically with the engaging means. When a pushbutton slide 1 is pressed a kick arm 2 is rotated to tilt the clutch lever 3 as shown in Fig. 3 so as to release frictional engagement at 17 of a gear 8 fixed to the shaft 4 and a gear 7 rotatable on the shaft. The clutch switching is accurate and the pushbutton operation is smooth because the spring 5 is positively held concentrically with the support shaft by engaging projections 16 on an annular protruberance 16a, Fig. 5 in an alternative form of the plate member 16. <IMAGE>

Description

SPECIFICATION Clutch mechanism for pushbutton tuner BACKGROUND OF THE INVENTION Field of the Invention This invention relates to a clutch mechanism for a pushbutton tuner, and more particularly to a clutch mechanism for a pushbutton tuner which is capable of always holding a spring acting to effect a clutch operation in a proper position to assure a stable clutch switching operation.

Description of the Prior Art In a pushbutton tuner, it is necessary that switching of stations be achieved by both a pushbutton operation and a manual operation.

For this reason, a clutch mechanism is provided in the manual operation system and actuated to be switched upon depression of a push button. In general, to achieve the switching operation, a clutch lever etc. is provided slidably on a shaft member and the clutch lever is normally urged by a spring to assure an interlocking position of the clutch mechanism and set free to release the interlocking of the clutch mechanism when the push button is actuated. In this conventional clutch mechanism, however, a coil spring 5 is simply fitted around the shaft member and the spring 5 is positioned eccentrically ralative to the shaft member as shown by a solid line in Fig. 6 because the member to urge is larger than the shaft member and accordingly the diameter of the spring 5 is larger than that of the shaft member. Thus, a stable operation cannot be assured.Sometimes, the spring 5 is slipped into between the components to hinder the clutch operation and cause troubles in the pushbutton operation, too.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a clutch mechanism for a pushbutton tuner which is capable of obviating the defects involved in the conventional mechanism.

In accordance with the present invention, there is provided a clutch mechanism for a pushbutton tuner which comprises: a plurality of button slides each fitted, at one end thereof, with a push button; a rotating shaft adapted to ratate by a manual operation; a means for inserting and drawing cores into and out of coils, respectively; a clutch means for transmitting rotation of the rotating shaft to the core inserting and drawing out means and keeping the rotation from being transmitted when the push button is depressed; said clutch means including a pair of rotation transmission members provided on a shaft and pressed against each other by a spring mounted on said shaft and held in a position by a holding member; one of said rotation transmission means being engaged with said rotating shaft;; a means responsive to displacenient of the button slide for compressing said spring and setting free said rotation transmission members.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a general perspective view of a pushbutton tuner equipped with a clutch mechanism in accordance with the present invention; Figure 2 is a vertical sectional view of the pushbutton tuner illustrated in Fig. 1; Figure 3 is a front view of the clutch mechanism employed in the pushbutton tuner illustrated in Fig. 1; Figure 4 is a perspective view of one form of a plate member; Figure 5 is a perspective view of a modified form of plate member; and Figure 6 is a side elevational view of a spring mounting state of a conventional clutch mechanism.

DESCRIPTION OF THE EMBODIMENT Referring now to the drawings, there is illustrated an embodiment of a clutch mechanism for a pushbutton tuner in accordance with the present invention. The pushbutton tuner has push buttons 11 arranged sidewise along the front of a casing 10 of the tuner and fitted to button slides 1, respectively.

Each of the button slides has a frequency control member 21. When the button slide is pushed inwardly upon depression of the push button, the frequency control member 21 acts on a bar 20a of a rotary crank 20 to ratate it.

As a result, a slide member 22 engaged with the rotary crank 20 is displaced along a guide rod 23 so that a core 24 provided at a rearward bent portion of the slide member 22 is inserted into and drawn out of a coil 25.

On the other hand, a worm gear 7 and a gear 8 as illustrated in Fig. 3 are provided so as to be rotated by operation of a manual rotating shaft 26 provided at an upper portion of the casing 10. Since the gear 8 is in mesh with a geared portion 27a formed on one side of a rotary crank 27, the rotary crank 20 is finely rotated to allow the core 24 to be put into or drawn out of the coil 25.

In the so arranged pushbutton tuner, a clutch mechanism having a frictional member 1 7 disposed between the gears 7 and 8 to change the interlocking relation between the worm gear 7 and the gear 8 which are interlocked with the rotational operation of the rotating shaft 26. More specifically, at least the worm gear 7 is slidable relative to support shaft 4. A clutch lever 3 and a spring 5 are fitted to the support shaft 4 at a portion extending inwardly from a gear mounting frame 9. One end of the spring 5 rests on a face of the clutch lever 3 and another end thereof rests on a place member 6 fixed at an end portion of the support shaft 4 by a locking ring 14. The clutch lever 3 has a passive portion 1 3 in the form of a step at a lower end of the clutch lever 3.An actuating portion of a kick arm 2 is arranged at a position engageable with the passive portion 1 3. When the button slide 1 is pushed inwardly, the kick arm 2 is first rotated to tilt the clutch lever 3 around its upper support portion 3a into a position shown by a phantom line in Fig. 3. As a result, the pressure of the spring 5 against the worm gear 7 through the gear mounting frame 9 is released and accordingly the interlocking relation between the gears 7 and 8 through the frictional member 1 7 is released. In accordance with the present invention, engaging portions 16, e.g. raised portions as depicted in Fig. 4, are arranged concentrically with the shaft on the plate member 6 and are engaged with said another end of the spring 5.The constructions of the engaging portions are not limited to that as illustrated in Fig. 4 and may be formed as an annular protuberance 1 6a as illustrated in Fig. 5 wherein a plate member 6a is made of a synthetic resin and the annular protuberance 1 6a is formed integrally with the plate member 6a.

Although the engaging portions 1 6 or the annular protuberance 1 6a engages with the inside of the spring 5 in the embodiments as illustrated in Figs. 4 and 5, the engaging portions 1 6 or the annular protuberance 1 6a may be adapted to engage with the outside of the spring 5.

In accordance with the present invention as described above, not only the clutch is actuated by depression of the button slide but the clutch switching operation is carried out accurately and the pushbutton operation is carried out smoothly because the spring 5 is positively held concentrically with the support shaft 4 by the engaging portions 1 6 or the annular protuberance 1 6a on the plate member 6. Furthermore, while the spring 5 in the conventional clutch mechanism should be a truncated conical coil spring as illustrated in Fig. 6 and described before, the spring is not limited to the truncated conical one and may be a common annular or cylindrical one in the present invention.

Claims (6)

1. A clutch mechanism for a pushbutton tuner which comprises: a plurali-y of button slides each fitted, at one end thereon with a push button; a rotating shaft adapted to rotate by a manual operation; a means for inserting and drawing cores into and out of coils, respectively; a clutch means for transmitting rotation of the rotating shaft to the core-inserting anddrawing-out means and keeping the rotation from being transmitted when the push button is depressed; said clutch means including a pair of rotation transmission members provided on a shaft and pressed against each other by a spring mounted on said shaft and held in a position by a holding member; One of said rotation transmission means being engaged with said rotating shaft;; a means responsive to displacement of the button slide for compressing said spring and setting free said rotation transmission members.

2. A clutch mechanism according to claim 1, wherein said holding member is a plate member fitted on said shaft and having an engaging means disposed concentrically with said shaft for engaging with an inside of said spring.

3. A clutch mechanism according to claim 1, wherein said holding member is a plate member fitted on said shaft and having an engaging means disposed concentrically with said shaft and engageable with an outside of the spring.

4. A clutch mechanism according to claim 2 or 3, wherein said engaging means is projections formed by cutting and raising peripheral portions of the plate member.

5. A clutch mechanism according to claim 2 or 3, wherein said engaging means is an annular protuberance formed integrally with said plate member and concentrically with said shaft.

6. A clutch mechanism for a push button tuner substantiailly as herein described with reference to and as shown in Figs. 1 to 5 of the accompanying drawings.