JPH0568593B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method and apparatus for compacting concrete in concrete placement work such as civil engineering and construction.

(Prior Art) Conventionally, bar-shaped concrete vibrator devices and portable devices incorporating a plurality of such devices have been used as concrete compaction methods and devices. This rod-shaped concrete vibrator device has one eccentric vibrator 2 or a planetary rotor built into a rod-shaped vibrating cylinder 1, as shown in FIGS. 2a and 2b, although detailed explanation is omitted in the figures. This is constructed by rotating it at a high speed of about 3,000 to 15,000 RPM using electric power or air force, thereby generating uniform vibration from the surface of the vibrating cylinder in each direction of the insertion site into the concrete, compacting the concrete. It was hot.

In recent years, with the increasing size of concrete construction, construction under harsh conditions such as on the seabed, and shortening of construction period, we will introduce concrete compaction methods and equipment that are important for these measures.
Engineering research results have been announced, but for example,
“Collection of papers from a symposium on the physical properties of fresh concrete and its application to construction,” 1988.
March 26-27, 2015, published by Japan Society of Civil Engineers, Concrete Construction Research Subcommittee, Jiro Murata and 2 others, Behavior of concrete by vibration compaction, pp. 107-112 (hereinafter referred to as conventional material). . Although not shown in this conventional document, two conventional flexible high-frequency vibrators, which are so-called bar-shaped concrete vibrators, are combined in parallel, and each vibrator is equipped with an eccentric weight of equal weight and rotates in opposite directions at a constant angular velocity. Basic engineering research has been conducted on compaction using various slumps using the vibrator, and the results have been disclosed.

(Problem to be Solved by the Invention) However, in the conventional technology, when the vibration speed of the vibrating tube increases due to the increase in the rotational speed of the vibrating shaft, the surface of the vibrating tube and the concrete during insertion operation into concrete. The proportion of vibration energy transferred from the vibrating cylinder to the concrete due to early separation or cavitation bubbles generated in the water in the mortar that is in contact with the vibrating cylinder surface, that is, the vibration transmission efficiency, increases as the vibration speed of the vibrating cylinder increases. It is logically clear that they are not proportional.

Therefore, there is a limit to increasing the compaction effect of concrete vibrators using conventional mechanisms.

The present invention aims to solve these problems and improve the concrete compaction effect of a bar-shaped concrete vibrator.

(Means for solving the problem) In order to solve the above problem, in the present invention, when the output of the vibrator is increased, one vibration is reduced in order to reduce the energy loss that occurs during vibration transmission. Instead of increasing the output of the shaft, the total energy transferred to the concrete can be increased by using multiple vibration shafts and dividing the energy thereby.

In other words, we focused on the fact that energy efficiency is improved and that vibrations in concrete can be amplified by simultaneously propagating multiple waves generated from multiple vibration axes into concrete and utilizing their interference effects. If you only do this, it will only have an effective effect on the concrete located in a certain direction with respect to the vibrating cylinder, so by rotating the entire vibration system at a low speed, it will be effective against the concrete in all directions from the vibrating cylinder surface. In other words, two rotating shafts with eccentric weights are installed in the vibrating cylinder of a bar-shaped concrete vibrator, and the rotating shafts are rotated in opposite directions at the same high speed. Inserting a multi-vibrating shaft concrete vibrator configured to rotate and revolve at a low speed around an intermediate portion of the two rotating shafts into the concrete compaction surface,
A vibration compaction method for concrete characterized in that compaction is performed in all directions near the vibrator, and two rotating shafts having eccentric weights are provided in the vibrating cylinder of the bar-shaped concrete vibrator, A concrete vibratory compaction apparatus is provided, comprising means for rotating the vibrating cylinder at the same high speed in opposite directions, and means for revolving the vibrating cylinder at a low speed around an intermediate portion between the two rotating shafts. did.

(Function) When the eccentric weight shaft is rotated at high speed within the vibrating cylinder and inserted into concrete, the wave front transmitted from one vibrating cylinder to the concrete is similar to that of rotating spiral-shaped mosquito coils as shown in Figure 3. state and spreads from the source to the surrounding area, and if the interval d of this wave front is the wave velocity c and the frequency of the vibrator is f, then d = c/f,
The embodiment of the present invention combines the rotation of two spiral lines as shown in FIG. On the line connecting them, that is, on the x-axis in Figure 4, the phases of the two waves are opposite and the amplitude is zero. In this way, the amplitude at any point from the vibration center is affected by the interference and the attenuation effect due to the propagation distance from the vibration source, so the equal amplitude line is x
Minimum in the axial direction and increasing with the deflection angle θ
It is maximum at =π/2. FIG. 5 illustrates this.

Therefore, by further rotating the two vibrating cylinders at a low speed around the midpoint of the two axes, the range of vibration effects on the concrete in all directions is expanded.

(Example) An example of the present invention will be described with reference to the drawings. 1st
Figure a is an explanatory diagram of the configuration of an embodiment of the present invention, Figure 1b
is a sectional perspective view of a main part.

In FIG. 1a, 20 is a vibrator main part, and the structure of the vibrator main part 20 will be explained in detail in FIG. 1b. Reference numeral 30 denotes a vibrator rotary drive machine. Although not shown, the vibrator rotary drive machine 30 is provided with a known means for revolving the vibrator main part 20 at a low speed, and is operated by an operation switch 32. The main part 20 of the vibrator, which is suspended in the concrete 21 indicated by the two-dot chain line, rotates in the direction of the arrow. 40 is an inverter for a vibrator. 50 is a controller for the rotary drive machine, 51 is a motor tachometer, 52 is a rotation speed adjustment, 53 is an operation switch, 54 is a power switch, and 31, 41, and 61 are wirings.

In Fig. 1b, 11 is a vibrating tube, 12 is a vibrating shaft, 13 is a hose, 14 is a motor section, 15 is a motor case, 16 is a connecting plate, 17 is a bearing, 1
8 is a twin adapter. Vibrator main part 2
0 is a twin adapter 18 supported by a hose 13
Motor case 15, 1 provided in a more parallel protruding manner
5 is supported by the connecting plate 16, and the vibration tube 1 is further supported by the connecting plate 16.
1 and 11 are provided protrudingly. Vibration tube 11
are provided with vibrating shafts 12, 12 having eccentric weights, and the vibrating shafts 12, 12 are connected to the motor case 1, respectively.
The motor parts 14 and 14 in the motor parts 5 and 15 are connected to each other. As shown in the figure, the connecting plate 16 is connected to the main part 2 of the vibrator.
It is equipped at the vibration node of 0. As configured as described above, in this embodiment, the motor cases 15, 15, which are provided in parallel and protruding from the twin adapter 18, are supported and tied together by the connecting plate 16, and the vibrating cylinder 11 having the eccentric weight that protrudes further. , 11 are rotated by motor parts 14, 14 in opposite directions at the same high speed,
The vibrator main part 20 inserted into the concrete 21 is caused to revolve from the rotary drive controller 50 by a low-speed revolution means (not shown) in the vibrator rotary drive machine 30, so that the concrete 21 is properly compacted. It will be done.

FIG. 3 is an explanatory diagram of waves propagating from one conventional vibrating tube, FIG. 4 is an explanatory diagram of waves propagating from two vibrating tubes according to an embodiment of the present invention and their interference, and FIG.
The figure is an explanatory diagram of equal amplitude lines when the revolution is stopped, but since it has been described above, its explanation will be omitted.

(Effects of the Invention) As described in detail above, according to the present invention, in a method and apparatus for compacting concrete in concrete pouring work such as civil engineering and construction using a bar-shaped concrete vibrator, there is provided a vibrating tube of the bar-shaped concrete vibrator. Two rotating shafts having eccentric weights inside are provided, and the rotating shafts are rotated at the same high speed in opposite directions, and at a low speed around an intermediate portion between the two rotating shafts. The constructed multi-vibration axis concrete vibrator is inserted into the compaction surface of concrete and compaction is performed in all directions near the vibrator, thus solving the conventional problems.Furthermore, the present invention improves the compaction of hard-mixed concrete. The result is a vibrator that works particularly effectively on general concrete, increasing work efficiency and improving concrete quality by expanding the effective compaction range of the vibrator, shortening the vibration time, and reducing the number of places where the vibrator can be inserted. It has the effect of bringing

[Brief explanation of the drawing]

FIG. 1a is a configuration explanatory diagram of an embodiment of the present invention, FIG. 1b is a sectional perspective view of a main part of an embodiment of the invention, FIG. 2a is a sectional view of a main part of a conventional bar-shaped concrete vibrator, Fig. 2b is an assembled external view of a conventional bar-shaped concrete vibrator, Fig. 3 is an explanatory diagram of waves propagating from one conventional vibrating cylinder, and Fig. 4 is an illustration of two vibrating cylinders according to an embodiment of the present invention. FIG. 5 is an explanatory diagram of waves propagating from and their interference, and FIG. 5 is an explanatory diagram of equal amplitude lines when the revolution is stopped. 1... Vibration tube, 2... Eccentric vibrator, 3... Rubber hose, 4... Motor section, 11... Vibration tube, 12
... Vibration shaft, 13 ... Hose, 14 ... Motor section, 15 ... Motor case, 16 ... Connection plate, 1
7...Bearing, 18...Twin adapter, 2
0...Vibrator main part, 21...Concrete, 30...Rotary drive machine for vibrator, 31...
... Wiring, 32... Operation switch, 40... Vibrator inverter, 41... Wiring, 50...
...Rotary drive machine controller, 61...Wiring, 51...
Motor tachometer, 52... Rotation speed adjustment, 53... Operation switch, 54... Power switch.

Claims (1)

[Scope of Claims] 1. A method for compacting concrete in concrete placement work for civil engineering, construction, etc. using a bar-shaped concrete vibrator, comprising two rotating shafts each having an eccentric weight in a vibrating cylinder of the bar-shaped concrete vibrator. A multi-vibration shaft concrete vibrator configured to rotate the rotating shafts in opposite directions at the same high speed and revolve at a low speed around the middle part of the two rotating shafts is installed on the concrete compaction surface. A vibratory compaction method for concrete characterized by inserting the vibrator into the vibrator and compacting it in all directions near the vibrator. 2. In a concrete compaction device for concrete placement work such as civil engineering and construction using a bar-shaped concrete vibrator, two rotating shafts each having an eccentric weight are provided in the vibrating cylinder of the bar-shaped concrete vibrator, and the rotating shafts are A vibratory compaction apparatus for concrete, comprising: means for rotating the vibrating cylinders in opposite directions at the same high speed; and means for revolving the vibrating cylinder at a low speed about an intermediate portion between the two rotating shafts.