JPH0136574Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to blades for a horizontal forced mixing concrete mixer, and the blades forming the mixer rotor blades are made of ceramic.

There are two types of concrete mixers: the gravity type, which simply rotates a cylindrical container with spiral blades surrounding it, and the forced mixing type, which has rotary blades inside a static can body. The kneading type takes less time to mix than the gravity type and has better mixing performance, so it is particularly suitable for mixing concrete with a slump of 3 cm or less. It is quite large and has disadvantages such as material being caught between the can body and the rotor, resulting in overload.

Incidentally, recently, wear parts of various machines, such as parts or cutting tools that were conventionally made of wear-resistant alloys, are being made of ceramic. In this case, ceramic has a hardness comparable to that of tungsten carbide, and has greater heat resistance.
Although it has advantages such as low affinity with metals at high temperatures, it is considered to be disadvantageous in areas subject to large impact loads because it is extremely brittle.

Here, to briefly explain the structure of the horizontal forced concrete mixer, as shown in Fig. 3, for example, four arms c... The half-moon-shaped blades d are attached by bolts to the end mounting seats of these arms c, diagonally intersecting the line along the drive shaft b, forming rotary blades. . In this way, each blade d...
is rotated close to the inner circumferential surface of the can body a by a drive shaft b that rotates approximately 20 times per minute to scrape up and mix the concrete material inside, but these blades d... are tilted to one side. Because the gravel is installed at a high speed and is moving at a fairly high speed, the slightly larger diameter gravel in the scraped up material is blown diagonally upwards and then falls and collides with the upper edge of the adjacent blade that is rising. There are many things. Furthermore, as mentioned above, if gravel is caught between the blade d and the inner surface of the can body a, a sudden pressure force is applied to the edge of the blade, so the blade is always struck first by the edge.
The surface will then be continuously abraded. It was also found that this hitting is mainly caused by impact force with almost no frictional force. This means that in terms of material, the edges that are hammered are strong against impact, but do not have to have particularly good abrasion resistance, and the surface area other than the edges is mainly designed for abrasion resistance, with no consideration given to impact. It's a good thing even if you don't have it.

The blade of this invention was developed focusing on the above points, and when the embodiment of this invention is described with reference to the drawings, the overall view is as shown in the plan view and longitudinal sectional view of Figs. 1 and 2. In this case, several ceramic pieces 4 are fitted into a fan-shaped base plate 1 with their upper surfaces aligned in one plane inside a base metal 3 which is formed into a shallow box shape by raising a peripheral edge 2 of a required height on a fan-shaped bottom plate 1. They are laid together and bonded to the base metal 3 with an adhesive. In addition, numeral 5 in the figure is a bolt for attaching and fixing this blade to the tip of the arm.
It is fixed to the base metal through a counterbore hole provided in the bottom plate part 1 of the arm, and is tightened and fixed across the mounting seat 6 at the tip of the arm. Further, the peripheral edge part 2 of the base metal 3 is made in advance by integrally with the bottom plate part 1 or by fixing a separate strip plate to the bottom plate part 1 by welding, and the height of the peripheral part 2 is the same as that of the ceramic piece 4... However, in this example the wear is about 3 lower than the surface of the ceramic piece. Furthermore, the ceramic used has high wear resistance, such as alumina, zirconia, silicon nitride, and silicon carbide.

This device has the above-mentioned structure, and as mentioned above, a strong impact force is applied to the edge of the blade that rotates along the inner surface of the can body, especially the area near the bottom of the blade, and the blade simply polymerizes ceramic on the surface. In the pasted version, the ceramic was broken and was not practical, but in this invention, the base metal 3 is formed into a shallow box shape, and the ceramic pieces 4 are fitted and glued inside. The piece 4... and the peripheral edge 2 of the base metal exhibit mutual material characteristics and can be used until both wear out almost uniformly. It also prevents sticking. The base metal 3 can be an ordinary iron product, and the ceramic 4 can be an ordinary one, such as a relatively inexpensive alumina-based one, so the whole can be made at low cost, and it can also be made to a certain standard size as shown in the figure. When making blades of various sizes by combining the required number of ceramic pieces 4..., each ceramic piece 4... is fixed against each other in the shallow box-shaped base metal 3, so there is little risk of it coming off. , has many advantages.

[Brief explanation of drawings]

FIG. 1 is a plan view of the blade of this invention, FIG. 2 is a side sectional view, and FIG. 3 is an explanatory slope view of the horizontal forced mixing concrete mixer. 1...Bottom plate part, 2...Peripheral part, 3...Base metal, 4
...ceramic piece, 5...bolts.

Claims (1)

[Scope of utility model registration request] It is a blade that is attached by bolts to the tip of each arm connected to a drive shaft installed horizontally through the can body, and is a base metal made of several ceramic pieces 4... in the shape of a shallow box with the desired outline in advance. Concrete mixer blades are formed into an integral plate-like structure.