TITLE OF THE INVENTION Conveying apparatus using a flexible screw-tube BACKGROUND OF THE INVENTION FIELD OF THE INVENTION This invention relates to an apparatus for conveying solid or fluid construction material such as concrete, bricks, tiles, sand and pebbles, or granular material such as grain, and, more particularly, to a conveying apparatus using a flexible screw-tube. The apparatus comprises a twofold flexible tube having a fixed outer tube and a rotatory inner tube which has a helical blade on its inside wall along the elongated direction thereof without a shaft. DESCRIPTION OF THE PRIOR ART Conventional apparatuses for transferring material can be typically divided into a pumping type for fluid material such as concrete, water or oil and a conveyer type for solid material such as grain, etc.

A pumping type apparatus has little difficulty with fluid material, but has much difficulty with such viscous, sticky or solid material as concrete paste, grain, pebbles, etc., because extra equipment such as a vacuum machine, etc. is needed, and this may cause an increase in cost for manufacturing and maintenance thereof.

One of the primary disadvantages of the conventional type conveyers is found in the fact that, apart from their demand for large manufacturing

expense, such as in the case of a vacuum apparatus, in their installation, they usually need wide spaces and, particularly, when there arises a need for shift of destination, they must be disassembled and reset for the new destination. This invariably results in work retardation and cost waste.

Conventional conveyers customarily comprise an elongat-ed straight tube within which is mounted a helical blade connected at one end to a source of power which rotates the blade shaft to move the material forward in a straight line, along the inside of the tube. Therefore, if there arises a need for changing the direction, a number of conveyers have to be joined together, for which some extra special equipment becomes necessary.

For example, Japanese patent publication No. Hei. 2-5008, discloses a screw conveyer capable of changing its conveyance direction for such solid and fluid material as earth and sand, introducing several straight tubes arranged so as to change the direction, and for this purpose, it adopts a special screw connecting element for each point of bending. Another example, using a universal joint at the bending part is found in Japanese patent publication No. Sho. 62-1145. But, these screw conveyers, in spite of having some advantage for changing of their transference direction to some degree, still are inconvenient, for

they need to be taken apart and reassembled whenever necessary. These types cannot be installed in small spaces.

SUMMARY OF THE INVENTION Accordingly, an objective of the present invention is to provide an apparatus for conveying solid and/or fluid material such as sand, pebbles, bricks,; grain, etc. in any direction within a certain degree of the bending angle of the tube without using any additional apparatus, which is also suitable to be installed even in small spaces like indoor construction areas.

The apparatus of the present invention comprises a flexible outer tube fixed to the main body of a driving means; a flexible inner tube having a helical blade on its inside wall and being rotatory within said outer tube; and a driving means to rotate the said inner tube.

DESCRIPTION OF THE DRAWINGS The invention will be described in greater detail with reference to the drawings in which :

Fig. 1 is a representation of a conveying apparatus using a flexible screw-tube of the present invention. Fig. 2 is a sectional view according to the line A-A' of Fig. 1.

Fig. 3 is a representation of a flexible screw-

tube according to the line B-B' of Fig. 2.

DETAILED DESCRIPTION OF THE INVENTION With reference to Figs. 1 to 3, the conveying apparatus of the present invention comprising a twofold flexible tube 2 and a driving means 1 is described in detail as follows :

An outer tube 2A, having one end fixed to the main body 10 of the driving means 1 and the other end (not drawn) free and opened, is composed of material flexible but having some hardness, and it serves as a housing to repress the shaking of the inner tube 2B when it rotates .

An inner tube 2B, being inserted in said outer tube 2A, is mounted so as to receive the turning force of a driver 20 at one end rotated by said turning force received, and it has a helical blade 2B' on its inside wall along the lengthwise direction.

The driving means 1 comprises a driver mounted on one side of the main body 10 and having a driving axle 21 and a worm 22; a rotary portion 30 supported on the main body 10 through bearings 31, having a worm gear 32 which is meshed with a worm 22, and fixing said inner tube 2B to its inside wall; a fixing portion 40, in the front area of the main body 10, to fix said outer tube 2A; and a hopper 50, attached to the rear area of the main body 10, and feeding the material to be conveyed.

The apparatus described above starts to convey the material by the operation of the driver 20. The material being fed through the hopper 50 is advanced into said inner tube 2B in feeding sequence, and the rotary portion 30 fixing the outer circumference of one end of said inner tube 2B can enforce the inner tube itself to rotate with the help of the worm gear 32 meshed- with worm 21 of driving axle 21, and in this, the rotatory direction is the same as the helical blade 2B' of inner tube 2B.

In order to increase the faculty to convey the material, a rope 52 whose sectional shape is rugged and whose one end is attached to the inner surface of the hopper 50 can be inserted lengthwise in the inner tube 2B.

The outer tube 2A surrounding the inner tube 2B is fixed to the front area of the main body 10 and the lubricant area 2C can absorb the frictional force caused by the fixation of the outer tube 2A. The lubricant area 2C may be made by maintenance of a certain gap between the two tubes, but as it is so difficult to maintain an even distance between the two tubes in actuality that a serious abrasion of touching face may occur (chiefly in the bottom area), it is preferable to drop the frictional force by means of filling up the gap between the two tubes with conventional lubricant oil.

The conveying apparatus using a flexible screw- tube according to the present invention is applicable to extensive circumstances irrespective of the space for installation, direction for conveyance, and kinds of material transferred, and it can be manufactured and operated inexpensively.