TECHNICAL FIELD

The present invention concerns a machine for producing metal fiber to be used as a reinforcement element in concrete casts in the production of reinforced concrete works, particularly floors and coverings. According to the international patent classification (IPC) the present invention can be classified in the next classes; B21 F 45/00, B21 F 1/04, B23D 31/00, B23P 17/06.

BACKGROUND OF THE INVENTION

In civil engineering industry metal fibers are used as a reinforcing element in concrete works like industrial floors, concrete coverings, concrete panels or suchlike. Metal fiber is a small shaped piece of metal wire that can be in many different shapes: corrugated, with hooked ends, serrated or some other shape that is used in civil engineering industry . The shape of metal fiber guarantee a better adherence with the concrete and hence to confer greater resistance and rigidity, particularly with reference to compression, to the structure to be made. Metal fiber usually have a length from 20mm to 70mm and with a diameter of from about 0,15mm to 1.3mm and in reinforced concrete replacing the metal mesh normally used. An example of metal fiber is shown in figure 7 of EP 1 695 775 A1.

Metal fibers are usually produced by means of machines comprising a drawing and shaping assembly and a cutting assembly.

Machines for producing metal fiber usually comprise drawing and shaping assembly and cutting assembly. Drawing and shaping assembly usually consist of one or more pairs of counter-rotating toothed wheels, rollers or endless chains which draws and shape simultaneously a plurality of metal wires to the desired shape. Cutting assembly usually consist of rotating or linear cutting knife located downstream of drawing and shaping assembly and performs the cutting to size simultaneously of all metal wires being worked.

Machine for producing metal fiber is known from patent documentation EP 1 695 775 A1 and also from patent documentation EP 0 428 399 A2.

Known construction solutions have disadvantages such as high consumption of electric energy, many built in elements which require more maintenance time. Because of large number of built in elements there is increased possibility for mechanical failure. Also there is a presence of leak of productivity and flexibility.

Drawing and shaping assembly can produce only one shape of metal fiber, so production of other shapes of metal fiber is not possibile or require change of drawing and shaping assembly and because of complicated construction that operation require more spent time.

A purpose of present invention is a machine characterized with small energy consumption, high productivity, with minimal maintenance time and with ease handling.

Another purpose of present invention is a machine that can produce different shapes of metal fiber along with short period of time needed for change of drawing and shaping assembly.

And another purpose of present invention is a mschine with small number of buil in elements what reducing possibility of mechanical failure.

DISCLOSURE OF INVENTION

Machine for producing metal fiber comprises two main assemblies: drawing and shaping assembly and cutting assembly located downstream of drawing and shaping assembly.

Both assemblies are mounted on the machine frame which provide machine leaning on the floor.

Drawing and shaping assembly consist of one pair of counter-rotating profiled cylinders, where one cylinder is driving and another one is chasing. Profiled cylinders perform feeding and shaping plurality of metal wires alligned paralel to each other. Cylinders are profiled in such way that one have positive shape of metal fiber and another one have negative shape of metal fiber. Centerlines of the cylinders are parallel to each other and located in the same plane. Cylinders simultaneously perform shaping and moving metal wires towards cutting assembly where processed metal wires being cut to the desired size.

Arc distance between profiles on the drawing and shaping cylinders is equal to the size of the metal fiber.

Drawing and shaping cylinders with metal wire have reciprocal contact at the point what results in small cylinders area used for shaping of metal wires, what provide high working speed, high productiity and small energy consumption.

Cutting assembly is located downstream of mentioned drawing and shaping assembly and consist of cutting knife in shape of the propeller used for cutting to the desired sizze all metal wires being worked.

Cutting knife centerline is parallel to the centerline of the drawing and shaping cylinders. Centerline of a cutting blade of a cutting knife covers the angle with a cutting knife centerline which provides cutting of shaped metal wires one by one. As a result there is smaller cutting force followed by less cutting energy. Rotation of the cutting knife is coordinated with rotation of the drawing and shaping cylinders in order to cut worked metal wires to the exact size. Coordinating is done by control and command unit.

In order to prevent intersection of plurality of metal wires and to achieve regular of metal wires guiding, a special guide profile is used. This guide profile is located in front of a driwing and shaping assembly and between driving and shaping assembly and cutting assembly.

BRIEF DESCRIPTIONS OF THE DRAWINGS

FIG. 1 shows a side view of the machine for producing metal fiber according to the invention.

FIG. 2 shows the section from A-A of the machine in FIG. 1 FIG. 3 shows isometric view of the drawing and shaping assembly FIG. 4 shows normal view of a metal wire leading guide FIG. 5 shows normal view of the cutting knife FIG. 6 shows machine integral parts and work method FIG. 7 shows a detail of FIGURE 6 FIG. 8 shows one shape of a metal fiber

DETAILED DESCRIPTION OF INVENTION

Machine for metal fiber production (shown in figure 1 and 2), comprises a machine frame 1 on which are mounted a drawing and shaping assembly 11 for shaping metal wires 5, able to shape simultaneously up to twenty four and more metal wires 5, and a cutting assembly 13 able to cut to desired size 28 shaped metal wires so as to obtain metal fiber 23.

Metal wire 5 winded on the spools 4 is through the support 3 lead to the wire editorial 2. Wire editorial 2 consists holes 17 which number is equal to the number of metal wires 5 being processed simultaneously. To prevent jamming diameter of the holes 17 is greater than a diameter of the metal wire 5. Wire editorial 2 is attached to the machine frame 1 with screws 18, achieving easy assembling and disassembling.

Drawing and shaping assembly 11 comprise at least a pair 10 of counter rotating profiled cylinders. Drawing and shaping assembly 11 performs shaping of metal wires 5 to the desired shape and also provides linear motion of shaped metal wires 5 to the cutting knife 19. Machine rotating elements are covered with housing 8

Pair 10 of counter rotating cylinders consists of driving 24 cylinder, which is powered with engine 20 by means of belt 21. Rotation direction of driving cylinder 24 is toward cutting knife 19. Surface area of the driving cylinder is profiled to have shape and size of the negative form of the metal fiber 23 to be made. Surface area of the chasing 25 cylinder is profiled to have shape and size of the positive form of the metal fiber 23. Length of the step 27 on the profiled surface is equal to the length 28 of the metal fiber 23. Direction of rotation of the chasing 25 cylinder is opposite from the direction of rotation of the driving 24 cylinder. Axes of both cylinders are parallel to each other. Pair 10 of the drawing and shaping cylinders is through bearings, which are not shown on the figure, mounted on the cylinder supports 15 which are connected with spindle 16. Spindle 16 provides linear movement of the chasing 25 cylinder in the plane orthogonal to the X axis, defining the diameter of the metal fiber 23. Cylinders supports 15 are connected to the machine frame 1 with screws 26 which provide simply and easy replacement of the drawing and shaping cylinders 24 and 25. Surface area of the cylinders 24 and 25 involved in shaping of metal wire 5 is small, resulting with lower energy consumption, high working speeds and high productivity. Beside for shaping, cylinders 24 and 25 are also used for drawing of metal wire 5 from the spools 4 and her translation toward the cutting knife 19.

Since plurality of metal wires 5 are being processed simultaneously, to prevent crossings or tangling of metal wires 5 lined up one to another, leading profile 12 is used. Leading profile 12 is shaped as a plate, with guide channels inside (not shown on figures), where number of channels matches the number of metal wires 5 being processed. Leading profiles 12 are mounted between wire editorial 2 and drawing and shaping assembly 11 , and also between drawing and shaping assembly 11 and the cutting knife 19. Leading profiles 12 is leaning on the machine frame 1 by mean of support plates 22.

Cutting assembly 13 is located downstream of said drawing and shaping assembly 11 and comprises a rotating cutting knife 19. Rotating cutting knife 19, when watching from the side, has the shape of the propeller. Cutting knife axis 31 is parallel to the axis of drawing and shaping cylinders 24 and 25. Cutting knife blade 29 with cutting knife axis 31 covers an angle 30 which provide gradual cutting of all metal wires 5 being processed to the desired size 28. Gradual cutting require less cutting power followed by less energy consumption.

Cutting knife 19 is leaned on the machine frame 1 by means of bearings 14.

Rotation speed of the cutting knife 19 is synchronized with the rotating speed of drawing and shaping cylinders 24 and 25 which is done by a command and control unit 9. This for result have cutting of shaped metal wire 5 to the desired size 28 to obtain metal fiber 23.

Produced metal fibers 23 are collecting in the bunker and possible waste products in the waste channel 7.