JPH0356154Y2 - - Google Patents

Description

[Detailed explanation of the invention] A. Purpose of the invention Industrial application field The invention is for holding lamps and directional antennas that are mounted on a base body that floats on the sea and tilts and oscillates, such as a light buoy or a ship. Concerning improvements to equipment.

Conventional technology When a light buoy or a directional antenna attached to a light buoy or ship that floats on the sea and tilts and oscillates is fixed to the light buoy or ship as is, the beam of light radiated from the light equipment and the directional antenna are The direction of the emitted (or received) radio waves fluctuates in exactly the same way as a light buoy or a ship tilts, and its direction cannot be determined. Therefore, it is common practice to attach lamps and directional antennas via gimbal devices. Light equipment and directional antennas attached to gimbal devices are insensitive to simple inclinations, but the only places that are subject to simple inclinations are light buoys and the center of gravity of a ship. In particular, lamps and directional antennas should originally be mounted near the top of the superstructure, so their positions are considerably higher than the center of gravity. Therefore, when these attached objects are swayed, they are not only subjected to a simple tilting oscillation external force, but also to lateral acceleration proportional to the distance from the center of gravity. Therefore, the lamp or directional antenna attached to the gimbal device will undergo an oscillating motion similar to when a pendulum is subjected to lateral acceleration.

Problems that the invention aims to solve: Even if a light fixture or directional antenna attached to a gimbal device is stably held horizontally due to gravitational acceleration, it will in principle have no choice but to tilt if it is subjected to lateral acceleration. do not have. When a light buoy or a ship is floating on the sea, it is forced to move rapidly due to waves, so the lights and directional antennas attached to the gimbal device are also subjected to sudden lateral acceleration, causing them to It will vibrate about the axis of The present invention aims to increase the chances that the lamp and directional antenna will maintain a horizontal state by terminating this unavoidable vibration in as short a time as possible.

B. Means for solving the structural problems of the invention In this invention, an oil damper is attached to each of the two axes of the gimbal device to which objects such as lamps and directional antennas (hereinafter referred to as objects) are attached. This suppresses the continuation of vibration. The details of the structure will be explained below with reference to the drawings.

FIG. 1 is a perspective view for explaining the principle and operation of the horizontal holding device according to the present invention, in which 1 is an object, 2
is fixed above the center of gravity of object 1 on the X axis. 3 is a gimbal ring that supports the X-axis with a bearing, 4
is a Y-axis fixed to the cymbal ring 3, 5 is a base that supports the Y-axis with a bearing, and 6 is an oil damper. The X-axis 2 and the Y-axis 4 are perpendicular to each other and lie on the same plane, and this plane is a horizontal plane when the machine is stable and stationary. The oil damper 6 is connected to the X axis 2 and the Y axis.
It is inserted between the arm 7 fixed to the shaft 4 and the gimbal ring 3 or the base 5, and is attached by a pin joint 8.

FIG. 2 is a sectional view showing the structure of the oil damper 6 shown in FIG. 1, and shows a cylinder 9 containing oil 14.
A piston 10 with a small hole 11 moves up and down. 12 is a piston rod that moves the piston up and down, and is fixed to the piston 10. Reference numeral 13 denotes a mounting hole, which constitutes a pin joint portion shown at 8 in FIG.

Function When the base 5 is fixed to a base body that tilts and oscillates and there is no oil damper 6, the attitude of the object 1 will not change if the base body is only tilted and will remain in a horizontal state, but if it receives lateral acceleration, the object 1 will move. 1 is gimbal axis 2
It begins to vibrate in a pendulum motion about the axes 4 and 4, and if there is no friction in the bearing, this oscillation continues at the unique period of this system and does not stop. X axis 2 and Y axis 4
When the oil damper 6 is attached to the gimbal ring 3 and the base 5 by the pin joint 8 via the arm 7 fixedly attached to the object 1, when the object 1 vibrates,
In the cylinder 9 of the oil damper 6, a piston 10 is moved up and down by a piston rod 12 against the oil 14 filled therein. At this time, the piston 10 receives resistance to its vertical movement due to the fluid resistance of the oil 14, and the vibrations of the object 1 are attenuated. If the size of the small hole 11 provided in the piston 10 is adjusted to increase the fluid resistance and, for example, create a critical vibration damping state, the vibration of the object 1 will stop at one cycle of the natural period of this system.

FIG. 3 is a graph showing the effects explained above. There are four graphs in Figure 3. A shows the situation where the inclination changes when the base body (light buoy or ship itself) receives sudden external force from waves etc. and tilts and sways, and B shows the situation where the inclination changes. It shows a change in the lateral acceleration applied to the object attachment part (i.e., the base 5) caused by the oscillation of the base body. C shows the vibration state around the gimbal axis of an object supported by a gimbal device without an oil damper 6, and D shows the vibration state of an object supported by a gimbal device with an oil damper 6, that is, the horizontal holding device according to the present invention. , is a graph showing the state of vibration around the gimbal axis. In this graph, the vertical axis represents the amount of change in amplitude or acceleration, and the horizontal axis represents elapsed time (for example, in seconds). Hereinafter, the horizontal axis will be referred to as the time axis.

In order to explain the graph shown in Figure 3 in detail,
FIG. 4 shows the relative relationship between the base (light buoy or ship itself) and the base 5. In Fig. 4, 15 is the base, 16 is the upper structure (mast or tower),
5 is the base shown in FIG. Figure 4 shows the base 15.
is on the sea and is tilted due to waves, the center of gravity of the base 15 is indicated by G, and from G the base 5
The height up to this point is indicated by H, and the maximum angle of inclination is indicated by θ. Note that 1 is an object shown in FIG. 1, which is supported on a base 5 by a gimbal shaft as in FIG.

The process of changing the inclination of the base 15 shown in graph A in FIG. 3 will be explained as follows. The base body 15 in FIG. 4 is subjected to a short-term forcing force due to waves, etc. (in graph A of FIG. 3, the base body 15 is subjected to a constant force for a period of time from -1 to 0 on the time axis, and the base body 15 is subjected to a maximum inclination angle θ.
When the forced force is released at that point, the base body 15 will freely oscillate with the natural oscillation period when the base body is floating, starting from time axis 0. (begins to be upset). The curve in graph A shows this situation. Therefore, the vertical axis in graph A is the base 15
When viewed as the movement of the base 5 in FIG. 4, it can be seen as the amplitude of the base 5 vibrating from side to side.

Graph B in FIG. 3 shows changes in lateral acceleration caused by the above-mentioned left-right vibration of the base 5. Regarding the amplitude of the horizontal vibration of the base 5 after 0 on the time axis, W¨=H・sinθ・cosωτ ≒H・θ・cosωτ ...(1) Here, W¨ is the amplitude and ω is the circular vibration. In numbers, ω=2π/
TT is the natural vibration period of the base 5. Therefore, the lateral acceleration is the second derivative of equation (1), and becomes W = -ω ² H (Axes -1 to -0) Only the acceleration due to forced force increases.

Graph C in FIG. 3 is a graph showing the amplitude of oscillation of object 1 when subjected to the lateral acceleration shown in graph B.
This figure shows a situation where the gimbal shafts are supported only by the gimbal shafts 2 and 4 without intervening, and there is almost no friction in the bearings. Due to the lateral acceleration received between time axis -1 and -0, it swings greatly and is left almost freely (since the lateral acceleration after time axis 0 in graph B is small, the excitation force ), large vibrations continue.

Graph D in FIG. 3 is the same as graph C, with an oil damper 6 interposed between the object 1 and the base 5,
This shows the vibration state of the object 1 when sufficient vibration damping is performed. In this case, the degree of damping is set to a critical damping state, and a situation is shown in which vibration of the object 1 is suppressed within one period of the natural period with respect to the base 5.

The natural period of the vibration of the object 1 with respect to the base 5 must be set to a value that is as far apart as possible from the value of the natural period T of the base 15 to avoid resonance. In this case, T
The value is set as small as possible.

Embodiment FIG. 5 shows a front view of a navigation aid lighting unit equipped with a leveling device according to the present invention, FIG. 6 shows a side view thereof, and FIG. 7 shows a plan view thereof. In Figs. 5 to 7 above, reference numeral 17 is a navigational aid lantern (hereinafter referred to as a lantern), and this cylindrical part serves as a lens, and a light bulb installed inside is used as a light source, and the optical axis surface 24 is It emits a beam of light in a 360° horizontal direction. 18 is a lantern mounting base on which the lantern is mounted and has one of the gimbal axes, the X-axis 2. 19 is a balance weight, which is attached to the bottom of the lantern mount. Therefore, the lantern 17, the lantern mounting base 18, and the balance weight 19 are integrated,
Object 1 of FIG. 1 is formed. By attaching the balance weight 19, the center of gravity of the object 1 is positioned lower than the gimbal position. As shown in the figure, the balance weight 19 has wind plates 20 arranged radially in order to balance the wind pressure between the upper part and the lower part of the gimbal axis when receiving a crosswind, so that the lantern does not tilt due to the wind. That's what I do. Reference numeral 21 denotes a guard ring, and when the lantern 17 tilts significantly and the lower end of the balance weight 19 swings, the lower end just touches it and restricts it from tilting further.It is fixed to the base 5. There is. Note that a rubber tire is attached to the lower end of the balance weight 19 to provide a buffering measure. Reference numeral 22 is an electric wire for supplying power from the outside to the inside of the lantern, and it is made long enough so as not to impede the freedom of movement of objects 1 such as the lantern 17. 23 is a relay box for relaying power supply from the outside. In the embodiment shown in this figure, oil dampers 6 are installed at both ends of the X-axis 2 and Y-axis 4 of the gimbal axes, so two oil dampers are installed on one axis.
It is equipped with several oil dampers. This means that when the piston 10 slides in the cylinder 9 within the oil damper when vibrating around each axis, one of the pistons 10 is always in contact with the oil 14.
This is to cause the piston 10 to move in the direction of compression, and to prevent the back surface of the piston 10 from becoming a vacuum and losing its damper function when it is under tension.

C. Effects of the invention The stronger the directivity of the lamps used for navigation aids and the antennas used for wireless communication, the higher the luminous intensity of the lamps and the higher the gain of the antennas. However, increasing the directivity requires increasing the stability with which the lamp or antenna is held in a particular direction.

The leveling device according to the present invention is a device that satisfies the above requirements and also has the economical advantage of not requiring special sensors or power. When equipped with a wireless antenna, it greatly contributes to energy saving and improved performance.

[Brief explanation of the drawing]

Fig. 1 is a perspective view for explaining the principle and operation of the horizontal holding device according to the present invention, Fig. 2 is a sectional view showing the structure of an oil damper used in this device, and Fig. 3 is a perspective view for explaining the principle and operation of the horizontal holding device according to the present invention. Figure 4 is an explanatory diagram of the environment in which the leveling device according to the present invention is used, and Figures 5 to 7 are graphs for explaining the sway of an object when using the device according to the present invention. FIG. 5 is a front view, FIG. 6 is a side view, and FIG. 7 is a plan view. The symbols in the figure are as follows. 1...object, 2
...Gimbal axis X axis, 3...Gimbal ring,
4... Y axis of the gimbal axis, 5... Base, 6... Oil damper, 7... Arm linking the gimbal axis and the oil damper, 9... Cylinder of the oil damper, 10... Piston of the oil damper, 1
7... Lantern, 18... Lantern mounting stand, 19...
balance weight.

Claims (1)

[Scope of utility model registration request] In a horizontal holding device that uses a gimbal device to stably hold an object even when the foundation tilts and sways, an oil damper that damps rotational motion is attached to each of the two orthogonal axes of the gimbal. A horizontal holding device with an oil damper, characterized in that the damping force is strong enough to quiet down free rotational vibrations about the gimbal axis of the object within a sufficiently short period of time compared to the period of the external force that shakes the object.