JP7469119B2 - Hose tip for pouring fresh concrete and its manufacturing method - Google Patents

Description

The present invention relates to a hose tip for pouring ready-mixed concrete in which a reinforcing wire is embedded in the middle of the thickness of the hose body, and to a method for manufacturing the same.

In general, concrete pump trucks are used to inject ready mixed concrete at construction sites such as apartment complexes and buildings. That is, ready mixed concrete is pumped using a concrete pump truck with a piping line, and the ready mixed concrete is discharged and supplied to a specified injection point from a tip hose located at the end of the piping line, which is the outlet for the ready mixed concrete. A technique for this type of work is disclosed in Patent Document 1.

When performing this ready-mix concrete injection work, the tip of the hose is generally moved to the designated injection point by an operator, and this is shown in the disclosure of Patent Document 2.

When pouring ready-mixed concrete using a concrete pump truck, the ready-mixed concrete is first lifted to a high position by a boom device, and then flows down forcefully, as if falling, through the end of the hose, which is in a nearly hanging position (see Fig. 2 of Patent Document 1 and Fig. 1 of Patent Document 2).

When the ready-mixed concrete materials (crushed stone and cement) flowed quickly through the hose at the end, they tended to separate. When ready-mixed concrete separates into different materials, it can lead to undesirable phenomena such as junk.

In order to prevent separation of the ready-mixed concrete material, the end hose has been designed with a section that has a flat cross section, as shown in Patent Document 3. This has the advantage that the flat cross section of the hose body is deformed to open up the cross section, as if a brake is being applied to the ready-mixed concrete as it flows down, minimizing the aforementioned material separation.

However, to make a hose tip with a flat cross section, rubber (flexible material) and synthetic fiber reinforcement cord must be layered on a circular mandrel, vulcanized, and then de-cored. The circular hose body must then be flattened using a jig or similar tool before being re-vulcanized, which roughly doubles the man-hours in the vulcanization process, resulting in high costs.

JP 2000-94434 A JP 2013-253620 A Japanese Utility Model Application Publication No. 63-8341

The objective of this invention is to provide an improved tip hose for pouring ready-mixed concrete, which has been reconsidered, including a review of the structure, to give the hose a flat cross section that is effective in preventing separation of the ready-mixed concrete material, while keeping the cost low.

The present invention relates to a tip hose for pouring fresh concrete,
The hose has a vulcanized rubber hose body 1, and a spiral steel cord 3 is embedded in the middle of the wall thickness of the hose body 1.
The reinforced hose portion 1H in which the steel cord 3 is embedded in the hose body 1 has a cylindrical cross section which is pressed flat to plastically deform the steel cord 3, and the cross section of the reinforced hose portion 1H is made flat by utilizing the plastic deformation of the steel cord 3 .

It is preferable that the cross-sectional shape of the reinforced hose portion 1H is set to an elliptical shape. And, it is more preferable that the steel cord 3 is formed by twisting together a plurality of unit wires 5, and that the unit wires 5 are formed by twisting together a plurality of unit wires 6.

It is advantageous if the flattening ratio τ (t/h), which is the ratio of the length of the short side t to the long side h in the cross section of the reinforced hose portion 1H, is set in the range of 0.2 to 0.55.

The second aspect of the present invention is a method for manufacturing a ready-mixed concrete pouring hose having a vulcanized rubber hose body, comprising:
The hose body 1 is prepared by embedding a spiral steel cord 3 in the middle of the wall thickness.
This manufacturing method is characterized in that a roller press process r is performed in which the hose body 1 is clamped between a pair of pressure rollers 8, 9 arranged closely opposite each other and forcibly transferred, thereby pressing flattening the reinforced hose portion 1H of the hose body 1 having a cylindrical cross section in which the steel cord 3 is embedded, thereby plastically deforming the steel cord 3, and by utilizing the plastic deformation of the steel cord 3, the cross section of the reinforced hose portion 1H is made into a flat shape.

The flexible material of the hose body 1 is rubber, and the roller press process r is a manufacturing method performed on the hose body 1 after vulcanization . It is more convenient if the steel cord 3 is formed by twisting together a plurality of unit wires 5, and the unit wires 5 are formed by twisting together a plurality of element wires 6.

According to the present invention, the cross section of the reinforced hose portion reinforced with steel cords is flattened, so that when the fresh concrete flows down the hose body (flowing down forcefully), it encounters moderate resistance to movement due to the internal passage with a narrow cross-sectional area of the flattened shape. This results in a separation prevention effect in which separation does not occur or hardly occurs between aggregate such as crushed stone and cement (mortar or cement paste) during flow.

And when the amount of ready-mixed concrete transported per unit time increases, the cross-sectional shape of the reinforcing hose section elastically deforms from an elliptical shape to something closer to a cylinder while providing the aforementioned resistance to movement to the ready-mixed concrete, resulting in a compliant expansion effect.

The steel cord used as the reinforcing layer has the characteristic that it is flexible and can utilize the plastic and elastic deformation of metal. Therefore, it was found that the reinforced hose part, in which this steel cord is embedded in a spiral shape and has a flat cross section, provides both the separation prevention effect and the follow-up expansion effect mentioned above.

Then, it was found that after the reinforced hose portion is manufactured as a product with a circular cross section, it can be made into a reinforced hose portion that can exert separation prevention effects and follow-up expansion effects simply by compressing (by pressing, etc.) so that the cross section becomes flat.

In other words, changing the cross-sectional shape from cylindrical to flattened can now be done with a single action, eliminating the need for a double vulcanization process, reducing the amount of processing required and lowering production costs, which in turn allows for cost reductions for the product as a whole.

As a result, through reexamination including a review of the structure, it has become possible to provide an improved tip hose for pouring ready-mixed concrete, with a hose cross section that has a flat shape that is effective in preventing separation of ready-mixed concrete materials, while keeping costs down.

In addition, according to the second invention, since the hose has a reinforced hose portion in which steel cords with moderate resilience are embedded, if the hose material is rubber, a flat cross section that can be elastically expanded and deformed can be obtained simply by performing a roller press process after vulcanization. In other words, the cross section can be made flat from a cylindrical shape with a single action process, which has the advantage of reducing production costs and ultimately reducing the cost of the product.

FIG. 1 shows a hose tip for pouring fresh concrete; (A) is a partially cutaway side view, and (B) is an enlarged rear view showing the flattened shape of the hose body. 1 shows a steel cord, (A) being a cross-sectional view and (B) being a plan view. FIG. 2A is a cross-sectional view of a main portion showing the structure of the base end portion of the distal end hose of FIG. 1; FIG. 2B is a rear view of the hose body; 1 shows a method for manufacturing a tip hose, in which (A) is a front view of a roller press process, and (B) is a side view showing an image of the roller press process.

Below, an embodiment of the tip hose for pouring ready-mixed concrete according to the present invention will be described with reference to the drawings. Note that from here on, the tip hose for pouring ready-mixed concrete will be abbreviated to "tip hose."

As shown in Figures 1(A) and 3(A), the distal end hose A is a long hose having a hose body 1 made of rubber (an example of a flexible material) and a tubular connection fitting 2 that is fitted into the base end of the hose body 1. The connection fitting 2 is a cylindrical fitting having a standard tubular portion 2a, a thick base end portion 2A formed at the base end, and a flange portion 2B formed in the middle of the standard tubular portion 2a in the longitudinal direction.

The hose body 1 has a hose base 1A that is fitted onto the connection fitting 2, and a reinforced hose portion 1H. The hose base 1A has a reinforcing layer (such as a reinforcing spiral wire or a fiber reinforcement cord wound in a spiral or circular shape) 10 embedded in the middle of its thickness, and a base end ring 11 is provided at the folded front end so as to be located on the base end side of the flange portion 2B.

The reinforcing layer 10 has an outer reinforcing portion 10A and an inner reinforcing portion 10B arranged radially inside the outer reinforcing portion 10A, and a base end ring 11 is housed in the folded base end 10b of the inner reinforcing portion 10B. The base end of the outer reinforcing portion 10A is overlapped adjacent to the radially outside of the folded base end 10b of the inner reinforcing portion 10B. The reinforcing layer 10 (outer reinforcing portion 10A and/or inner reinforcing portion 10B) is arranged radially inside the steel cord 3 (described later) in the hose body 1.

The reinforced hose portion 1H has a spiral steel cord 3 embedded in the middle of its thickness, and a reinforcing layer 10 is embedded in the front end of the reinforced hose portion 1H. As shown in Figures 1(A) and (B), the reinforced hose portion 1H is configured so that its cross section is flattened, more specifically, elliptical, except for its base end.

In other words, the reinforced hose portion 1H has a cylindrical cross-sectional portion 1e with a circular cross-sectional shape, a flat cross-sectional portion 1h with an elliptical cross-sectional shape, and a cross-sectional change portion 1c between the cylindrical cross-sectional portion 1e and the flat cross-sectional portion 1h. In other words, the hose length is 1H = 1e + 1c + 1h. Note that, of the hose body 1, the portion outside the reinforcing layer 10 and the steel cord 3 is called the outer rubber layer 12, and the portion inside is called the inner rubber layer 13.

As shown in FIG. 1(B), the flattening ratio τ (t/h), which is the ratio of the length of the short side t to the long side h in the cross section of the reinforced hose portion 1H, is set in the range of 0.2 to 0.55, i.e., 20%≦τ≦55%. In FIG. 1(B), the cross-sectional shape of the reinforced hose portion 1H is depicted as an ellipse with a flattening ratio τ (t/h) of approximately 0.36 (36%) as an example. The cross-sectional shape of the reinforced hose portion 1H may be a shape other than an ellipse, such as an oval or a rectangle with rounded corners.

As shown in Figures 2(A) and (B), the steel cord 3 housed inside the hose body 1 is formed by twisting together a number of unit wires 5, and the unit wires 5 are formed by twisting together a number of wires 6. Specifically, the unit wires 5, which are side strands, are formed by Z-twisting seven wires 6, and the cord line 4 is formed by Z-twisting five unit wires 5 with a core strand 14 located in the center. The core strand 14 is formed by S-twisting three wires 6.

The steel cord 3 is constructed by winding a spiral wrap wire 7 around the cord wire 4, which is made up of five twisted unit wires 5. The wrap wire 7 is twisted in the opposite direction to the twist direction of the unit wires 5, i.e., S-twisted, on the outside of the cord wire 4. The steel cord 3 constructed as described above is wound spirally inside the rubber of the reinforcing hose portion 1H. The wires 6 and wrap wire 7 are wire materials such as steel wire or piano wire.

Next, the main points of the manufacturing method for the tip hose A will be explained. As shown in Figures 4(A) and (B), a processing machine B is prepared, which is made up of an upper pressure roller 8 and a lower pressure roller 9 arranged close to each other in the vertical direction, and a hose body 1 is prepared, in which a spiral steel cord 3 is embedded in the middle part of the wall thickness. This hose body 1 is cylindrical, as shown in Figures 3(A) and (B).

For example, in the processing machine B shown in the image diagram of FIG. 4(B), the upper pressure roller 8 is pivoted on a support shaft 8a, and the lower pressure roller 9 is pivoted on a support shaft 9a. In addition, multiple guide rollers 15 are provided to gradually change the cross section of the cylindrical reinforced hose portion 1H before processing and guide it to the pair of pressure rollers 8, 9, but the structure of the processing machine B is not limited to this.

Then, a roller pressing process r is performed in which the hose body 1 is clamped between a pair of pressure rollers 8, 9 arranged closely facing each other and forcibly moved, so that the cross section of the reinforced hose portion 1H in which the steel cord 3 is embedded in the hose body 1 can be made into a flat shape.

In this case, between the pair of pressure rollers 8 and 9, the steel cord is completely crushed and deformed into an oval shape (rounded corners) as shown in Figure 4 (A), but after passing through the pair of pressure rollers 8 and 9, the kickback (resilience) of the material (raw material) causes the steel cord to settle into the elliptical shape shown in Figure 1 (B). In other words, due to the material properties of the steel cord 3, the steel cord is not completely crushed and deformed, and the elliptical shape ensures a passage of a certain cross-sectional area, and the reinforced hose portion 1H is obtained in a state in which it is possible for the steel cord to undergo elastic deformation to expand in diameter from its elliptical cross-sectional shape toward a cylinder.

[About the effects]
It has been found that when pouring fresh concrete using tip hose A (see Figures 1 and 3) having a hose body 1 with a flat cross section due to its elliptical shape, the narrow cross-sectional area results in moderate resistance to the fresh concrete as it flows down the internal passage of reinforced hose portion 1H, compared to when the cross section is circular.

Therefore, when pouring work is performed using the tip hose of the present invention with an elliptical cross section, separation between aggregates such as crushed stone and mortar (or cement paste) does not occur or occurs very little (separation prevention effect). In addition, it was found that when the amount of ready-mixed concrete transported per unit time increases, the cross-sectional shape of the reinforcing hose portion 1H flexibly elastically deforms from an elliptical shape to approach a cylindrical shape while providing the aforementioned movement resistance to the ready-mixed concrete, and an effect of being able to respond (following expansion effect) is also achieved.

It was found that when the cross-sectional flatness τ of the reinforced hose portion 1H is less than 0.2 (less than 20%), the original cross-sectional area is small and fresh concrete passage is poor, and when the flatness τ is greater than 0.55 (55%), the original cross-sectional area is large and the effect of suppressing junk is not sufficiently achieved. Therefore, by setting the flatness τ in the range of 0.2 to 0.55 [20%≦τ(t/h)≦55%], it is possible to provide a tip hose A that enables smooth transfer of fresh concrete while suppressing junk.

The tip hose A shown in Figures 1 and 3 has a reinforced hose portion 1H in which a steel cord 3 with moderate resilience is embedded, so that a flat cross section that can be elastically expanded and deformed can be obtained simply by performing the roller press process r using the processing machine B after vulcanization.

After making and vulcanizing the cylindrical tip hose A shown in Figure 3, the tip hose A with the flattened cross section shown in Figure 1 can be obtained simply by performing the roller press process r using the processing machine B. In other words, a single action of processing is sufficient to change the cross section shape from cylindrical to flat, which eliminates the need for a double vulcanization process, reducing production costs and ultimately offering the advantage of making the product more affordable.

[Additional explanation]
In conventional tip hoses, a reinforcing layer to maintain the shape is made of hard steel wire or piano wire wound in a spiral at an equal pitch, but in tip hose A of the present invention, this is replaced with a steel cord 3, giving the hose body 1 a flattened shape. The advantage of a reinforcing layer made of steel cord 3 is that it makes use of the plastic deformation and elastic deformation of metal, and is flexible.

The method for producing the flattened hose body 1 involves continuously compressing a perfectly circular hose (see Figure 3) in which steel cord 3 is wound in a spiral shape at an equal pitch, into a flattened state. The hose can be made flat (see Figure 1) by plastically deforming the steel cord 3 on both sides. After being flattened, it has a flattened shape (elliptical shape) due to plastic deformation, but when fresh concrete is passed through it is easy to make the internal passage of the reinforcing hose part 1H follow the shape and amount of fresh concrete passing through by utilizing elastic deformation.

The restoring force of the reinforced hose section 1H when fresh concrete passes through it can be varied in any way depending on the diameter of the wire 6 of the steel cord 3, the presence or absence of a wrap wire (wrapping wire) 7, the winding pitch, the cord winding pitch when forming the hose body 1, and the twisting structure.

The diameter of the wire 6 can be, for example, 0.15 mm, but considering bending fatigue, 0.30 mm or less is preferable. Increasing the number of twists with a thick wire 6 increases the rigidity, and it is thought that the resistance to the flow of fresh concrete will increase (become too large). In addition, the winding pitch of the wrap wire 7 (when spirally wound around the reinforcing cord of the hose) depends on the wire diameter and number of twists used, but should be in the range of 6 to 13 mm.

[Another embodiment]
The number of unit wires 5 in the steel cord 3 may be a multiple other than five, such as four or six, and the number of wires 6 may be a multiple other than seven. In addition, the core strand 14 may be present or absent, and the number of wires 6 may be a multiple other than three, and the presence or absence of wrap wires 7 may also be changed as desired.

1 Hose body 1H Reinforced hose portion 3 Steel cord 4 Cord wire 5 Unit wire 6 Wire 8, 9 Pressing roller r Roller pressing process h Long side t Short side τ Flattening ratio

Claims (6)

The hose has a vulcanized rubber hose body, and a spiral steel cord is embedded in the middle of the wall thickness of the hose body.
The reinforced hose portion in which the steel cord is embedded in the hose body has a cylindrical cross section that is flattened by pressing to plastically deform the steel cord, and the plastic deformation of the steel cord is utilized to give the reinforced hose portion a flat cross section.This is a tip hose for pouring ready-mixed concrete. The tip hose for pouring ready-mixed concrete according to claim 1, wherein the cross-sectional shape of the reinforcing hose portion is set to an elliptical shape. The ready-mixed concrete pouring hose tip according to claim 1 or 2, wherein the steel cord is formed by twisting together a plurality of unit wires, and the unit wires are formed by twisting together a plurality of unit wires. A ready-mixed concrete pouring hose tip according to any one of claims 1 to 3, in which the flattening ratio, which is the ratio of the length of the short side to the long side in the cross section of the reinforced hose portion, is set in the range of 20% or more and 55% or less. A method for manufacturing a tip hose for pouring fresh concrete having a vulcanized hose body made of rubber , comprising:
As the hose body, a hose body having a spiral steel cord embedded in the middle part of the wall thickness is prepared,
A manufacturing method for a tip hose for pouring ready-mixed concrete, in which the hose body is clamped between a pair of pressure rollers arranged closely opposite each other and forcibly moved, by a roller press process, the reinforced hose portion of the hose body having a cylindrical cross section in which the steel cord is embedded is pressed flattened to plastically deform the steel cord, and the cross section of the reinforced hose portion is made flat by utilizing the plastic deformation of the steel cord . The method for manufacturing a tip hose for pouring ready-mixed concrete according to claim 5, wherein the steel cord is formed by twisting together a plurality of unit wires, and the unit wire is formed by twisting together a plurality of unit wires .

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