JPS6221924B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in the beam of a beam-type vibratory compaction device.

The conventional beam 1 of a beam-type vibratory compaction device used for concrete finishers, etc.
As shown in Figures a, b, and c, long lengths of standard length (e.g.
m), medium length (e.g. 4.5m), short length (e.g. 3m)
There are beams 1a, 1b, 1c, and depending on the road width to be applied in each case, at both ends of one of the standard beams, for example 0.75 m, 0.5 m, 0.25 m as shown in Fig. 1 d, e, f. m attached beam 1d,1
Either e or 1f is combined to form an integrated beam. Then, a beam length matching a predetermined road width is formed, and the paving material is compacted by vibration by a vibrator 2 provided on the upper surface 1A of the beam 1 as shown in FIG. 1b.

However, especially for beams of medium length or larger,
When the beam is vibrated by the vibrator 2, the frequency used may match the natural frequency of the standard beam or the integral beam. As a result, the beam may resonate and be destroyed, so in order to prevent the beam from being destroyed, the beam must be made more robust than necessary to avoid the effects of resonance.

By the way, in the beam type vibration compaction device,
The beam was designed to be easy to attach to equipment, connect to each other, and reduce the number of connection points to match the type of beam to be prepared and the width of the road.
It is advantageous to have fewer beams attached to the stand device. For example, if a single compaction beam is used in a device for compacting the roadbed of railway tracks,
If there is a protrusion in the center of the roadbed, it will buffer against the protrusion, causing problems such as making it impossible to compact the left and right sides of the protrusion. In order to solve this problem, there is a system in which the beam is divided and each is mounted independently on the device. However, since the divided beams need to be compacted and vibrated independently, they are not integrated by connection, as a matter of course. As a result, the natural frequency of the divided beams may match the used frequency as described above. At that time, it is necessary to prevent the beam from causing resonance, and there is a problem in which countermeasures such as increasing the rigidity as described above must be taken.

As described above, it is an object of the present invention to provide a beam-type vibratory compaction device that can avoid resonance during beam vibration without increasing beam strength.

The present invention is based on the knowledge that even if the total length of the beam is the same, if the beam is a combination of several short beams, its natural frequency will be lower than that of an integral beam. It is based on To be more specific, as shown in Figure 2, the horizontal axis is the beam length L (m), the vertical axis is the natural frequency vpm of the beam due to the vibrating body, and the natural frequency is calculated by changing the integral beam length one after another. According to the calculation results and experimental results, the change in the natural frequency of the integral beam is like the curve α, which intersects the range A of 4000 to 4500 vpm, which is the frequency used in compaction work. When the number of short split beams connected is increased to make them the same length as the integral beam, the change in the natural frequency of the connected beam becomes as shown by the curve β.Furthermore, when a shim is inserted at each connection surface, the range It has been found that the natural frequency decreases within B, and that the natural frequency of the beam can be set lower than the curve α without intersecting the range A of frequencies used. This is because when short split beams are joined to form a beam with a length equivalent to a medium or long beam, the stiffness of the bolted joint becomes lower than the bending stiffness of the beam, so the stiffness of the entire connected beam increases. This is because it is possible to reduce the amount of vibration and the natural frequency. In addition, it was also confirmed that depending on how the shims were interposed, the reduction could be further reduced.

The present invention was made based on the above findings,
The feature is that it is a beam-type vibratory compaction device that divides the beam into short lengths and connects an appropriate number of the divided beams with bolts to keep the natural frequency of the entire connected beam away from the operating frequency. That's what I did.

Hereinafter, the present invention will be explained in detail based on examples thereof.

Figures 3a, b, and 3c show front views of long, medium, and short beams, which are standard beams used in the beam-type vibratory compaction apparatus of the present invention. Shown in Figure 3b
For a standard beam of 4.5m, its connecting beam 13
For example, three short split beams 13 with a length of 1.5 m
a, 13b, 13c, for example, four bolt holes 10 as shown in FIG. 4a, FIG.
They are connected by bolts 14 shown in c.

In addition, each divided beam 13a of the connection beam 13,
A thin shim 12 as shown in FIG.
As shown in the figure, a step surface 11a may be formed on each connection surface 11 to reduce the bonding area on the connection surface 11.

Such a connecting beam 13 is equipped with an oscillator 2 having the same configuration as the conventional one, and the oscillator 2 is connected to an appropriate number of oscillators 3 fixed to the upper surface 13A and the beam 1.
A drive source for the oscillator 3 (not shown) provided in the center of the oscillator 3, an appropriate number of shafts 5 rotated by its belt 4, etc., and an upper surface 1 that rotatably supports the shafts 5.
Appropriate number of bearings 6 and their shafts 5 fixed to 3A
When the oscillators 3 are rotated from the drive source via the belt 4, etc., each oscillator 3, which has an appropriate unbalance weight built-in, becomes in a rotating state. Vibration is generated, and the entire connecting beam 13 can be brought into a vibrating state with a desired frequency.

An appropriate number of frames 9 are provided on the upper surface 13A of the connecting beam 13 to connect the main body of the beam-type vibratory compaction device (not shown) via anti-vibration rubber 8. Therefore, the vibration of the connecting beam 13 is reduced. It is designed so that the vibration is not transmitted to the main body of the beam type vibration compaction device.

By the way, in the case of long or short standard beams as shown in FIG.
It goes without saying that b... is connected. The lengths of the divided beams 13a etc. are as described above.
The length is not limited to 1.5 m, and can be appropriately selected so as to have a natural frequency that does not cause resonance when combined. Of course, as in the past, when the standard length beams that are a combination of these cannot cope with the width of the road, additional beams as shown in FIGS. 1d to 1f are connected.

Since the beam of the beam-type vibratory compaction device is constructed of a connecting beam consisting of an appropriate number of divided beams as described above, it can be operated as follows.

In this case, what should be noted is that compared to the natural frequency of the integral beam as described in FIG. Since the beam does not move and cross the frequency used by the beam, it is possible to always avoid resonance.

In other words, since there is no need to change the frequency used in accordance with the natural frequency of the beam to avoid resonance, the oscillator 3 can be set to a suitable frequency for concrete compaction.
It can be rotated at 4000 to 4500 vpm, and the entire connecting beam 13 can be kept at a working frequency of 4000 to 4500 vpm at all times. Although the natural frequency of the connecting beam 13 is passed through while reaching the usable frequency, it passes instantaneously and does not cause any resonance phenomenon.

Therefore, there is no need for the entire connecting beam to be destroyed by resonance, as in an integral beam, or for the entire connecting beam to be made unnecessarily robust in order to prevent beam destruction.

In other words, by dividing the integral beam into short lengths and connecting an appropriate number of divided beams with bolts, the rigidity is lower than that of the integral beam, and at the same time, the natural frequency is also lowered.

In other words, it is possible to suppress the increase in weight of the beam without applying any special reinforcement to the beam, to make it possible to create a beam with dimensions equivalent to medium-sized or long beams, and to prevent it from resonating at the frequency used. I can do it. This takes advantage of the fact that the stiffness of bolt connections is lower than the bending stiffness of the beam.
It is based on moving the natural frequency of the entire connecting beam away from the operating frequency.

As explained in detail above, the present invention divides the beam into short lengths and connects an appropriate number of the divided beams with bolts, thereby making the natural frequency of the entire connected beam far from the frequency of use. It is possible to avoid a resonance phenomenon caused by the frequency of vibration applied to the entire connecting beam of the mold vibration compaction device. Therefore, destruction of the connecting beam can be prevented, and there is no need to make the connecting beam more robust than necessary.

In addition, since the beam is made of a combination of short split beams, when creating a beam length suitable for various road widths, the desired length can be easily achieved by combining an appropriate number of split beams and an attached beam. can be obtained. Therefore, as in the past, the standard long length,
Compared to the medium-length, short-length beams, and attached beams that correspond to each road width, there are fewer types of beams,
In other words, only a few split beams and attached beams are required, and an appropriate amount of split beams can be held and combined, making it possible to use standard beams that previously had to be prepared to be applied to various road widths. There is an advantage that the total required beam length can be significantly shorter than the total required length of the attached beam. In addition, if the divided beam lengths are made the same, manufacturing becomes extremely easy, mass production is possible, and manufacturing costs can be reduced.

[Brief explanation of the drawing]

Figures 1a, b, and c are front views of the beams of conventional beam-type vibratory compaction equipment, Figures 1d, e, and f are front views of conventional attached beams, and Figure 2 is the beam length and beam characteristics. Graphs showing the relationship with vibration frequency; Figures 3a, b, and c are front views of the connecting beam of the beam-type vibratory compaction device of the present invention; Figures 4a, b, and c are front views of the connecting surfaces of the split beams. Figure 4 d is the same figure b -
5 is a plan view of a connecting surface having a stepped surface. 2... Vibrating body, 11... Connection surface, 11a... Step surface,
12...Shim, 13...Connection beam, 13a to 13d
...split beam, 14...volts.

Claims (1)

[Scope of Claims] 1. A beam-type vibratory compaction device that has a vibratory body on a beam that is supported by vibration isolation, and vibrates the entire beam by the vibrating force of the vibratory compaction device, in which the beam is divided into short lengths, and the beam is divided into short pieces. A beam-type vibratory compaction device characterized by connecting an appropriate number of beams with bolts so that the natural frequency of the entire connected beam is kept away from the operating frequency. 2. The beam-type vibratory compaction device according to claim 1, characterized in that a shim is interposed between the connecting surfaces of the divided beams. 3. The beam-type vibratory compaction device according to claim 1 or 2, characterized in that the connection surfaces of the split beams are formed with stepped surfaces that do not come into contact during connection.