JPH0523269Y2 - - Google Patents

Description

[Detailed description of the invention] ``Industrial application field'' This invention automatically adjusts the amplitude of a vibrating body that generates vibrations using the excitation force generated by rotating a weight with an eccentric center of gravity. It is related to a vibrating body that can be changed, and the field of application is, for example, when compacting sand, concrete, granules, powder, etc., the amplitude can be changed from low amplitude to high amplitude, or from high amplitude to high amplitude. It can be used as an excitation means that can automatically change the amplitude to a low amplitude.

[Prior Art] Conventionally, a method of changing the amplitude of a vibrating body was to change the amplitude by changing the overlapping angle of a pair of eccentric weights to an arbitrary position.

Therefore, when changing the amplitude, the rotation of the vibrating body must be stopped, which is inconvenient and requires manual labor and time.

Another method is to fix one eccentric weight A of a pair of eccentric weights A and B to a rotating shaft, and allow the other eccentric weight B to freely rotate on the rotating shaft, so that normal rotation and Change the overlapping angle with reverse rotation,
There is a method that makes it possible to obtain two types of amplitude. However, it has been impossible to continuously change the amplitude while vibrating.

``Problems that the invention attempts to solve'' This invention solves the above drawbacks and automatically changes the amplitude from low amplitude to high amplitude or from high amplitude to low amplitude while continuously generating vibration. The purpose is to provide a vibrating body that can be changed.

``Means for Solving the Problems'' An example of implementing the present invention as an automatic amplitude adjustment vibrating body will be explained based on the drawings.As shown in Figures 1 and 2, A weight 2 whose center of gravity is eccentric and fixed to a rotating shaft 1, a movable weight 3 whose center of gravity is movable and which is attached in the opposite direction to the weight 2 with respect to the rotating shaft 1, and a movable weight 3 that is fixed and held. The lever 5 that holds the movable weight 3 whose center of gravity has moved in the moved position, the support fitting 6 that supports the elastic body 4, and the movable weight 3 to prevent it from moving more than necessary. It is comprised of a stopper 7 for stopping.

``Operation'' When this vibrating body is rotated, an excitation force is generated according to the following general equation.

F=w _O /g・r・ω ² (1 equation) ω=2πN/60 F: Excitation force Kgf w _O : Eccentric weight Kg N: Rotation speed rpm r: Eccentric distance cm g: Gravitational acceleration 980cm/sec ² Initially, during low-speed rotation, the elastic force of the elastic body 4 that holds the moving weight 3 in the opposite direction to the rotating shaft 1 than the centrifugal force acting on the moving weight 3 is stronger than the centrifugal force acting on the moving weight 3. Because of the strong Excitation force is generated in the state where the

Furthermore, as the rotation speed increases, the centrifugal force acting on the moving weight 3 also increases, but the elastic force of the elastic body 4 holding the moving weight 3 outweighs this centrifugal force. The weight does not move until it reaches the number of revolutions.

However, when the rotation speed is increased further, the centrifugal force acting on the movable weight 3 increases further, and the elastic body 4 becomes larger than the elastic force holding the movable weight 3, and the centrifugal force causes the movable weight to move. The weight 3 begins to press and bend the elastic body 4. By moving this moving weight 3,
The position of the combined center of gravity of the weight and the movable weight 3 changes toward the center of the rotating shaft 1, and the eccentric distance decreases, resulting in a change in the excitation force.

Therefore, as shown in the general formula (1), when the rotational speed is increased, the excitation force increases in proportion to the square of the rotational speed, so a very large excitation force will be generated. It is dangerous. However, in the case of the present invention, even if the rotation speed is increased, the excitation force does not increase in proportion to the square of the vibration force, and the elastic force of the elastic body 4 and the movable weight 3
The excitation force can be automatically changed by changing the eccentric distance depending on the strength of the centrifugal force acting on the object.

The elastic body 4 has an elastic force stronger than the centrifugal force acting on the movable weight 3 until the rotational speed at which the excitation force is desired to be changed is reached, and both ends are supported by support fittings 6 in a slidable state. The fulcrum metal fitting 6 is supported by a pin from the weight 2 and has a structure that allows it to rotate freely. Further, a stopper 8 is provided as a safety measure to prevent the movable weight 3 from moving more than necessary due to centrifugal force and to prevent the movable weight 3 from moving in the direction of the rotation axis.

Here, a general formula for vibration amplitude is shown.

a=1.8/(N/1000) ²・F/W (2 formulas) a: Total amplitude mm F: Excitation force Kgf W: Vibrated weight Kg N: Rotational speed rpm (Formula 1) and (Formula 2) From the general formula, when the weight to be vibrated is constant, if only the rotation speed is changed without changing the eccentric weight or eccentric distance, the excitation force will change in proportion to the square, but the amplitude will not change. is clear. However, if the eccentric weight or eccentric distance is changed by changing the rotational speed, the amplitude can be changed. In the case of the present invention, the amplitude is automatically adjusted by changing the eccentric distance.

Next, when it is necessary to stop the rotation while the movable weight 3 is moving at a low amplitude due to high-speed rotation, or when it is necessary to increase the rotation from a stopped state to high-speed rotation while maintaining a low amplitude. In some cases, this can be done by the following method.

As shown in FIGS. 3 and 4, the lever 5 has a structure in which it can freely rotate around a fulcrum pin 8 provided on the weight 2. As shown in FIGS.

When the rotating shaft 1 is rotated to the left, the lever 5 tries to swing due to the centrifugal force acting on its own weight, but it cannot swing until the movable weight 3 starts moving.
As the rotational speed further increases and the movable weight 3 moves, the lever 5 swings and is no longer in contact with the elastic body 4. When the rotation speed is reduced from this low amplitude state, the lever 5 swings to the left (rotation direction) due to the inertia force acting on itself, and the lever 5
The corner part hits the weight 2 and becomes upright. Then, the centrifugal force also decreases and the movable weight 3 begins to return to its original position, but it is held at a low amplitude position by the lever 5, and even if the rotation is stopped, the movable weight 3 is moved back to the The elastic force remains applied.

Further, when the rotating shaft 1 is rotated clockwise, the lever 5 swings in the same manner as when rotating the rotating shaft 1 to the left. However, when the number of rotations is decreased, the lever 5 swings to the right (direction of rotation) due to the inertial force acting on itself and returns to its original direction, and the movable weight 3 is not held. .

Therefore, by rotating the rotating shaft 1 to the left, the movable weight 3 can be fixed in a low amplitude state,
When the movable weight 3 is rotated clockwise, the movable weight 3 is not fixed and the amplitude can be changed automatically.
Initially, the state of low frequency vibration with high amplitude at low speed rotation can be continuously changed to high frequency vibration with high amplitude and low amplitude by increasing the rotation as it is. Moreover, it is also possible to change from an initially low-speed rotation and low-amplitude state to a low-amplitude, high-frequency vibration.

An example of the use of the automatic amplitude adjustment vibrating body of the present invention will be explained based on the drawings. As shown in Figures 5 and 6, for example, sand, concrete, granules, powder, etc. are poured into the formwork. As a means for vibrating the formwork during compaction, the automatic amplitude adjustment vibrating body 13 of the present invention is attached to the formwork 11 attached to the fixed part 9 via the vibration isolating member 10 with a bearing 12. Pulley 1 is a prime mover that can be supported in one piece or in multiple pieces and can continuously and freely change the rotation speed.
The amplitude of the formwork 11 can be automatically changed by driving the rotating shaft 1 through the rotary shaft 4 and changing the rotational speed and by changing the direction of rotation.

``Effects'' When using the automatic amplitude adjustment vibrating body of the present invention, for example, when putting sand, concrete, granules, powder, etc. into a formwork and compacting it by vibration, it is first rotated at a low speed with a high amplitude. By compacting with low frequency vibration and then increasing the rotation, it becomes high frequency vibration with low amplitude at high speed rotation, and by decreasing the rotation, it is possible to change continuously from high frequency vibration to low frequency vibration. . By changing the direction of rotation, it is also possible to stop at a low amplitude state or to start driving from a low amplitude state.

Therefore, compared to the conventional methods of compaction using only low-frequency vibrations or compaction using only high-frequency vibrations, the automatically adjustable amplitude vibrator of the present invention has the following advantages:
Low-frequency vibration, which is effective against coarse objects such as sand and granules, and high-frequency vibration, which is effective against fine objects, such as cement and powder, are performed without stopping the vibration. Since the frequency can be changed continuously from low frequency to high frequency, or from high frequency to low frequency, the compaction effect is significantly improved, the quality of the product is improved in terms of density, strength, appearance, etc., and the manufacturing time is reduced. This contributes to shortening etc.

[Brief explanation of drawings]

Fig. 1 is a perspective view of an embodiment of the present invention, Fig. 2 is a front sectional view of Fig. 1, Figs. 3 and 4 are sectional views taken along A-A, and Fig. 5 is a use of the embodiment of the present invention. Example front view,
FIG. 6 is a plan view of FIG. 5. 1... Rotating axis, 2... Weight, 3... Moving weight,
4...Elastic body, 5...Lever, 6...Supporting metal fittings,
7...stopper, 8...fulcrum pin, 9...fixing part, 10...vibration isolating member, 11...formwork, 12...
Bearing, 13... Automatic amplitude adjustment vibrator of the present invention, 1
4...Pulley.

Claims (1)

[Scope of utility model registration request] A weight 2 whose center of gravity is eccentric and is fixed to a rotating shaft 1 driven by a prime mover, and a weight 2 whose center of gravity is eccentric with respect to the rotating shaft 1.
A movable weight 3 whose center of gravity can be moved in the opposite direction, an elastic body 4 that fixes and holds the movable weight 3, and a lever that holds the movable weight 3 whose center of gravity has moved at the moved position. 5, a support fitting 6 for supporting the elastic body 4, and a stopper 7 for preventing the movable weight 3 from moving more than necessary.