JPS6349925Y2 - - Google Patents

Description

[Detailed description of the invention] This invention is an automatic extension device that allows multi-stage poles with different diameters to fit together in a telescopic manner, automatically expands and contracts using the power of an electric motor, and automatically stops at the extension/contraction limit of the multi-stage poles. It is related to.

The above-mentioned automatic expansion and contraction devices are used in places that require expansion and contraction of equipment in various industrial fields, but for the sake of explanation, we will use an example of an automatic expansion and contraction device for an antenna element made of multi-stage poles mounted on a car. This is explained below.

Generally, an automatic extension/retraction device for a multistage pole fixes one end of a flexible drive cord to the proximal end of the smallest diameter pole, inserts this drive cord into a pole with a larger diameter than the smallest diameter pole, and then The end is locked to a rotating drum, and the rotational force of the electric motor is transmitted to the rotating drum by decelerating it with a worm or spur gear to transmit the appropriate rotational speed and torque.
The multistage pole is expanded and contracted by winding and unwinding the drive cord by rotating the rotating drum forward and backward.

When the telescoping pole reaches its telescoping limit, it becomes overloaded and if this condition continues, the motor will burn out, so in conventional automatic telescoping devices, there is no slipping clutch or mesh between the rotating drum and the worm wheel. A clutch or the like is used to prevent overload from acting on the motor due to idling. Also,
The electric motor power switch is automatically turned off at the same time as the clutch is released, or a little later.

Conventionally, the following methods have been used to turn off the power to the electric motor of the fully automatic telescoping device as described above. In other words, there are devices that have a timer circuit and use the timer to set the time from the start to the end of the expansion and contraction operation of the antenna element, and this is structurally simple because the timer circuit can be made independent. However, accurate time adjustment is difficult. There is also a device that is equipped with a rotating lever that is linked to the worm wheel, moves the lever each time the worm wheel rotates, and turns off the power with the lever after several rotations of the worm wheel, and this is currently widely used. However, the structure is complicated, and errors occur in the feeding of the rotary lever each time the worm wheel rotates due to wear and tear from long-term use. Furthermore, some devices turn off the power switch by axial movement of the clutch plate during overload, but since the axial movement of the clutch plate is a minute distance, the switch that detects this movement must be accurately positioned within the device. Not only is it difficult to install the switch, but the location where the switch is installed is susceptible to the effects of rainwater, etc., and malfunctions are likely to occur due to corrosion of the contacts.

The present invention attempts to eliminate the drawbacks of the conventional device as described above, and consists of a rotating drum that winds and returns a flexible drive cord that extends and retracts a telescopic multi-stage pole, and an electric motor that rotates this drum. A differential gear mechanism having a planetary gear is interposed between the differential gear mechanism, and an internal gear that meshes with the planetary gear of the differential gear mechanism is frictionally engaged with a rotation receiving case in which the rotating drum is pivotally supported. By turning off the power of the electric motor by the sliding rotation of the internal gear of the differential gear mechanism due to overload at the extension limit of the pole, the motor can be stopped with a quick and accurate response, and the structure is simple. It is also compact and lightweight, requires only a small and low-output electric motor, and prevents the switch that turns off the electric motor from being affected by external influences such as rainwater splashing on it. The purpose is to provide a telescopic device.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a flexible drive cord with one end fixed to the base end of a minimum diameter pole (not shown) of an antenna element consisting of multistage poles. The other end is locked to the inner drum 2a made of synthetic resin,
It is designed to be wound up and rewound on the outer peripheral surface of this. A drive cord 1 is attached to the inner drum 2a.
An outer drum 2b covering the outer drum 2b is fixed with screws.
The rotating drum 2 is rotatably supported by a rotation receiving case 3 around a central shaft 4, and a fixing nut 5 is attached to the central shaft 4.
is screwed on. An internal gear 6 is formed on the inner peripheral surface of the inner drum 2a, and an output gear 8 of a differential gear mechanism 7, which will be described later, is meshed with the internal gear 6. The differential gear mechanism 7, as shown in FIGS. 1 to 3,
A sun gear 10 is meshed with a rotating shaft 9a of a small electric motor 9 which is housed in an interior surrounded by the rotating drum 2 and the case 3 and which is fixed outside the case 3 and is capable of forward and reverse rotation. The planetary gears 11 are meshed with each other, and the internal gears 12 are meshed with the planetary gears 11. In addition, the gear shaft 11a of the planetary gear 11
is fitted and supported by the output gear 8 rotatably fitted to the rotating shaft 9a of the electric motor 9 and a support plate 13, and the internal gear 12 is fitted into the case 3 with its outer peripheral surface frictionally engaged. are combined. An arc-shaped recess 12a is formed in a part of the outer peripheral surface of the internal gear 12, and a roller-shaped member 14a of an internal switch 14, which will be described later, is fitted into this recess 12a. Internal switch 14
In this case, fixed contacts 14c and 14d are arranged on both sides of a movable contact 14b having a roller-shaped member 14a fixed to its tip, and these contacts 14b, 14c and 14d are attached to the case 3 via an insulating support member 15. ing. As shown in FIG. 4, the power supply circuit for the electric motor 9 is connected to the power source side via the internal switch 14 and the external operation switch 16. Note that symbols 16a and 16b in FIG. 4 are movable contacts of the external operation switch 16, and symbols 17 in FIG.
18 is a drum cover, 18 is an outer tube in which the antenna element is housed, and 12b in FIG. Further, the output gear 8, the sun gear 1
0, the planetary gear 11 and the internal gear 12 are made of synthetic resin.

Next, the operation of the automatic telescoping device of the embodiment configured as described above will be explained. As shown in FIG. 4, when the movable contact 14b of the internal switch 14 is in contact with the fixed contacts 14c and 14d, the external operation switch 16 is operated so that the movable contacts 16a and 16
b from the neutral state, one side connects the (+) side of the power supply directly to the electric motor 9, and the other side connects the (-) side to the electric motor 9 via the movable contact 14b and fixed contact 14d of the internal switch 14. rotates forward. The rotation of the electric motor 9 is caused by the planetary gear 1 via the sun gear 10.
1, and as these rotate and revolve, the output gear 8 rotates, and since the output gear 8 meshes with the internal gear 6, the rotating drum 2 rotates. As the rotary drum 2 rotates, the drive cord 1 is wound around the inner drum 2a, and the multistage pole constituting the antenna element is shortened. When the multi-stage pole reaches its shortening limit, the expansion and contraction are locked, resulting in an overload condition, but at this time, the planetary gear 11 is prevented from revolving and only rotates on its own axis.
The rotation of the sun gear 10 is transmitted to the internal gear 12 via the planetary gear 11. This results in
The internal gear 12 of the differential gear mechanism 7, which was fixed by frictional engagement with the case 2, rotates, and the roller-like member 14a tries to displace from the recess 12a of the internal gear 12, and at the same time as it starts to displace. The movable contact 14b separates from the fixed contact 14d, and the electric motor 9 is powered off. The inertial force thereafter is extremely small, and the internal gear 12 stops with a slight rotation, and the movable contact 14b of the internal switch 14 is maintained in contact with the other fixed contact 14c. Note that the notch groove 12b of the internal gear 12 is provided as a safety measure in the event of over-rotation.

Then, by switching the external operation switch 16, one of the movable contacts 16a and 16b is connected to the movable contact 14b and the fixed contact 14c of the internal switch 14.
When the (-) side of the power source is connected to the electric motor 9 through the power source, and the (+) side of the power source is connected directly to the electric motor 9, the electric motor 9 is reversed and the rotating drum 2 is rotated in the reverse direction through the differential gear mechanism 7. However, since the drive cord 1 is rewound, the multi-stage pole is extended, and the electric motor 9 is stopped at the extension limit due to the same action as at the shortening limit.

As mentioned above, the automatic extension/retraction device of this embodiment eliminates the need for a separate safety mechanism for the clutch as in conventional devices, and in conventional devices, the clutch does not click due to the inertia of the electric motor even if the electric motor is turned off. This produces a meshing sound, but this can be eliminated and the noise can be eliminated, and the space required for the clutch is also not required. In addition, since this embodiment uses a differential gear mechanism with planetary gears, it is possible to use a high-speed, low-torque electric motor such as those used in toys. By incorporating an automatic stop mechanism having gears and roller-like members, the electric motor and the driving force transmission system can be made smaller and lighter. Furthermore, since the device of this embodiment utilizes a differential using a planetary gear, it is possible to eliminate the unreasonable force that is output due to the inertia of the electric motor and gears when the clutch is turned off in the conventional device. The inertial force is very small, and the internal gear stops by rotating within the case by a small angle, making it possible to create a simple and compact automatic stopping mechanism.

The automatic expansion and contraction device of the present invention can be widely applied not only to the expansion and contraction of antenna elements for automobiles, but also to the expansion and contraction of expansion and contraction multi-stage poles of various devices.

As explained above, the automatic telescoping device of the present invention uses a differential gear mechanism with planetary gears to transmit power from an electric motor to a rotating drum that winds and unwinds a flexible cable. Since the electric motor is stopped by frictionally engaging the receiving case and rotating the internal gear only at the extension/contraction limit of the multistage pole, it is possible to quickly and accurately respond and automatically stop the motor at the extension/contraction limit. The electric motor does not burn out due to overload, the structure is simple and compact, and the differential gear mechanism and automatic stop switch are installed inside the rotating drum and rotating receiving case. Therefore, the installation space for these devices is small, and the switch is less susceptible to external influences such as rainwater.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of the main parts of an automatic telescopic device according to an embodiment of the present invention taken horizontally from the central axis when viewed from the bottom, Fig. 2 is a cross-sectional view of the same differential gear mechanism, and Fig. 3 is a cross-sectional view of the same differential gear mechanism. 2 is a side view, and FIG. 4 is a power supply circuit diagram of the motor. 1... Drive cord, 2... Rotating drum, 3
... Rotation receiving case, 6 ... Internal gear, 7 ... Differential gear mechanism, 8 ... Output gear, 9 ... Electric motor, 1
0...Sun gear, 11...Planet gear, 12...Internal gear, 12a...Recess, 14...Internal switch, 14a...Rolled member, 14b...Movable contact, 14c, 14d...Fixed contact .

Claims (1)

[Scope of utility model registration request] A flexible drive cord that is connected to a telescopic multistage pole to extend and retract the pole, a rotating drum that winds and unwinds the drive cord, a rotating receiving case that rotatably supports the rotating drum, and the rotating drum. and a differential gear mechanism that is housed inside a rotation receiving case and has an output gear that meshes with an internal gear provided on the inner peripheral surface of the rotating drum, and an electric motor that transmits power to the sun gear of this differential gear mechanism. A planetary gear that meshes with the sun gear of the differential gear mechanism is meshed with an internal gear that is frictionally engaged with the rotation receiving case, and a power supply circuit of the electric motor is provided with An automatic telescoping device characterized by being equipped with a switch that is turned off when the internal gear of the differential gear mechanism slips and rotates due to overload.