KR20010048390A - Wire tension controller for process line of unbonded pc strand - Google Patents

Abstract

PURPOSE: A strand tension regulator of an unbonded PC strand manufacturing line is provided to improve the quality of products by equalizing a plastic coating layer of an unbonded PC strand and enhancing external appearance. CONSTITUTION: A strand tension regulator(20) of an unbonded PC strand manufacturing line comprises a frame(21) erected on a moving route of a strand(W), a roller bracket(22) vertically supported on the upper end of the frame, a roller group(23) composed of many movable rollers(23a') and fixed rollers(23b,23b',2b'') attached on the roller bracket, roller feed gears(24,24') for reciprocating the movable roller and an air brake(25) combined to a central shaft of the roller(23b') to control the rotation of the roller.

Description

Wire tension controller for process line of unbonded pc strand}

The present invention relates to an apparatus for manufacturing an unbonded PC strand, and more particularly, to a tension control apparatus for maintaining a constant tension of a supply strand in front of a supply stage of an unbonded PC strand. The present invention relates to a wire tension control device of an unbonded PC strand production line which is installed to prevent vibration of strands so that plastic coating performed between movements of strands is smoothly performed.

In general, PC (Prestressed Concrete) is applied to compress concrete in advance by using steel wire or stranded wire to compensate for the low tensile stress, which is a disadvantage of concrete, and is widely used in various fields of civil construction in recent years. Coming.

As a material for applying a compressive stress to the PC product, a PC steel wire made of a single wire and a PC strand of a twisted wire of several strands are mainly used.

Recently, grease or wax is applied to the surface of the strand, and then the outside is coated with polyethylene (PE), high density polyethylene (HDPE), etc. so that the outside of the strand is surrounded by a plastic coating layer. Unbonded pc strands have been developed and utilized.

The unbonded PC strand is used in various fields, such as for stay cable of cable stayed bridge, earth & rock anchor, PC bridge, and rockfall prevention, the approximate structure of which is shown in FIG. have.

As shown, the unbonded PC strand 1 is coated with a lubricant such as grease 3 or wax around the strand 2 formed by twisting multiple strands of steel strand 2a together, and again the lubricant coated surface. The outer side of this structure has a structure in which a plastic coating layer 4 such as polyethylene (PE) is coated.

The manufacturing process of such an unbonded PC strand 1 will be described with reference to the schematic diagram of the unbonded PC strand production line shown in FIG.

First, the strand wire (2) mounted on the supply table (5) is drawn out and moved by the drive of the supply side caterpillar (6) installed in front of it, at this time, the grease coating device on the strand line moving path passing the supply side caterpillar (6) (7) and the plastic coating device (8) is provided so that the coating of the plastic coating layer (4) following the application of the grease (3) between the movement of the strand.

Subsequently, the stranded wire on which the plastic coating layer 4 is formed is cooled by passing through the cooling bath 9, and then moved to the winding machine 12 through the winding side caterpillar 10 and the traverse 11 and wound around the winding reel. The production of the Deid PC strand will be completed.

However, in the conventional unbonded PC strand production apparatus, when the strands released from the supply table are not constantly uncoiled, the vibrations occur or the strands are squeezed under the strands and pulled repeatedly. Such vibrations or oscillations are transmitted to the winder 12 through the continuous plastic coating device 8 in a straight line.

In particular, when there is vibration or the like of the strand 2a passing through the plastic coating apparatus 8, a defect occurs in the appearance quality such that the outer circumferential surface of the plastic coating layer 4 formed on the surface of the strand does not form a circle. In the case of severe vibration, the thickness deviation of the coated plastic coating layer becomes severe.

In addition, the vibration of the stranded wire as described above may lead to the winding machine 12 to cause a winding failure.

The present invention has been made in view of the above problems raised in the conventional unbonded PC strand production apparatus, by installing a tension control device to maintain a constant tension of the supply strand in front of the supply base plastic coating Strands of the unbonded PC strand production line that minimizes the winding failure in the winder, as well as smoothly coating the plastic between the movement of the strands by preventing vibration of the strands that are finally moved to the winder past the device. An object of the invention is to provide a tension control device.

1 is a perspective view showing the structure of an unbonded PC strand.

Figure 2 is a schematic diagram of an unbonded PC strand production line.

Figure 3 is a front view of the strand tension control device of the present invention.

Figure 4 is a side view of the strand tension control device of the present invention.

((Description of the code for the main part of the drawing))

1. Unbonded PC strand 4. Plastic coating layer

5. Supply Table 7. Grease Coating Device

8. Plastic Coating Equipment 12. Winding Machine

20. Tension control device 21. Frame

22. Roller bracket 23. Roller group

23a, 23a '. Movable Rollers 23b, 23b ', 23b ". Fixed Rollers

23b'a. Central axis 24, 24 '. Roller feeder

25. Air brake device 25a. Tension disk

The above object of the present invention is an unbonded PC strand configured to have a grease applicator and a plastic coating device installed on a strand movement path between a feeder and a winder, so that a coating of a plastic coating layer following the application of grease to the surface of the strand is made. In the manufacturing apparatus, it is achieved by a strand tension adjusting device that prevents vibration or oscillation of strands released from the feed stage in front of the feed stage.

The strand tension control device of the present invention is preferably installed on the strand moving path between the supply table and the supply side caterpillar.

The tension adjusting device includes a frame vertically mounted on the ground on the strand moving path, a roller bracket vertically supported at the upper end of the frame, a roller group including a plurality of movable rollers and fixed rollers mounted on the roller bracket, and the movable member. It consists of a roller movement handle for allowing the roller to move up and down, and an air brake device coupled to the central axis of any one of the fixed rollers to control the rotation of the roller.

At this time, the roller group is composed of three fixed rollers installed in a straight line while maintaining the same height and two movable rollers installed on top of these fixed rollers to allow relative vertical movement to the fixed roller side.

Each roller has a semicircular groove formed on its outer circumferential surface, and as the strand passes between the movable roller and the fixed roller, the roller in contact with the wire rotates about the central axis by the movement of the strand. .

Next, the air brake device extends the central axis of the roller positioned in the middle of the fixed rollers to the opposite side of the roller bracket, mounts the tension disk at its extended end, and provides a disk brake pad driven by pneumatic pressure around one side of the tension disk. It consists of an installed configuration.

Details of the above object and technical configuration and the effects thereof according to the present invention will be clearly understood by the following detailed description with reference to the drawings showing preferred embodiments of the present invention.

First, the overall structure of the unbonded PC strand production apparatus of the present invention is the same as the apparatus shown in FIG. However, in the present invention, there is a technical feature in that the tension adjusting device as shown in FIGS. 3 and 4 is installed in the strand moving section between the supply table 5 and the supply side caterpillar 6 in FIG.

As shown in Figures 3 and 4, the wire tension control device 20 of the present invention is composed of a frame 21 perpendicular to the ground on the strand (W) moving path, and has a substantially "b" shape frame ( 21, a plurality of movable rollers 23a, 23a 'and fixed rollers 23b, 23b' mounted on a roller bracket 22 which is vertically supported at the upper end of the roller 21; 23b "), the roller conveying apparatus 24 (24 ') and the said fixed roller 23b (23b') which make the lifting and lowering movement of the said movable rollers 23a and 23a 'possible. The air brake device 25 is coupled to the central axis 23b'a of any one of the rollers 23b 'and controls the rotation of the rollers.

At this time, the height of the frame 21 and the roller bracket 22 passes while the strand W is in contact with the upper outer peripheral surface of each of the fixed rollers 23b, 23b ', 23b "mounted on the roller bracket 22. It must be designed so that the height can be maintained.

The roller group 23 is installed and fixed on the three fixed rollers (23b) (23b ') (23b ") installed in a straight line along the strand (W) conveying direction while maintaining the same height and fixed on the top of these fixed rollers It consists of two movable rollers 23a and 23a 'installed so as to allow relative vertical movement to the roller side.

Each of the rollers 23a, 23a ', 23b, 23b' and 23b "has a semicircular groove c formed on its outer circumferential surface, and movable rollers 23a and 23a 'are lowered to fix the rollers. As the strand W passes between the movable roller and the fixed roller when it is brought into close proximity to (23b) (23b ') and (23b "), the rollers in contact with the wires are moved by the movement of the strands. It will rotate about its axis.

On the other hand, each movable roller (23a) (23a ') is configured to be moved up and down by the roller feeder (24, 24'), for this purpose roller feeder (24, 24 ') is a roller bracket (22) and a movable roller coupled to the lower portion of the conveying screw and the conveying screw (24b) and '24'b configured to move up or down by rotation of the adjusting handle (24a) and (24'a) mounted on the upper end of the (22). It consists of roller engaging holes 24c and 24'c which make vertical conveyance of 23a and 23a 'take place.

Next, the air brake device 25 extends the central axis 23b'a of the roller 23b 'positioned in the middle of the fixed rollers to the opposite side of the roller bracket 22, and at the extension end 25a of the tension disk 25a. ) And a disk brake pad 25b driven by pneumatic pressure around one side of the tension disk. In the figure, reference numeral 26 denotes an air tank.

At this time, the strength of the pressing force against the contact surface of the tension disk 25a is adjusted by adjusting the supply hydraulic pressure of the disk braking pad 25b positioned in close or close contact with both outer peripheral surfaces of the tension disk 25a. As a structure, the rotation of the tension disk 25a which rotates together with the fixed roller 23b 'is controlled.

Looking at the production process of the strand product in the unbonded PC strand production line equipped with the strand tension control device of the present invention made as described above are as follows.

The overall manufacturing process of the PC strand is identical to that discussed above in the prior art description. However, as part of the difference, the strand released from the supply table 5 passes through the strand tension adjusting device of the present invention before passing the supply side caterpillar 6.

At this time, the lower half of the strand W is inserted into the groove c formed on the outer circumferential surfaces of the lower fixing rollers 23b, 23b 'and 23b ", and the adjustment handles of the roller conveying devices 24 and 24' 24a) When 24'a is operated to lower the movable rollers 23a and 23a ', the upper half of the strand is fitted into the outer circumferential surface groove c so that all the rollers come into contact with the surface of the wire W. It is in a state.

The positional relationship between the movable rollers 23a, 23a 'and the fixed rollers 23b, 23b', 23b "is such that the lower end of each movable roller is kept slightly lower than the upper end of each fixed roller. It is desirable to allow the rotation of the roller to be made without slippage between the roller and the strand during the movement of (W).

As such, when the movable rollers 23a, 23a 'and the fixed rollers 23b, 23b', 23b "are brought into zigzag tight contact with the surface of the strand W, the rollers are moved. The rotation of the two is made so that the tension disk 25a coupled on the central axis (23b'a) of the central fixing roller (23b ') is also rotated.

In this state, the tension adjustment of the strand W is achieved by appropriately controlling the amount of air supplied to the disk brake pad 25b in frictional contact with the tension disk 25a.

As described above, the strands W passing through contact with the rollers 23a, 23a ', 23b, 23b', and 23b "in the state where the air brake device 25 is properly adjusted are tension adjusting devices. (20) The wire exiting the tension control device 20 is always maintained in a constant tension state, regardless of whether the strand before the passage is vibrating or rocking.

In other words, the strand (W) exiting the tension control device 20 of the present invention and finally moving the section up to the winder 12 allows the constant speed to move along a straight path without any vibration or shaking. Therefore, the plastic coating process performed between such movements is performed smoothly so that the entire outer circumferential surface of the plastic coating layer formed on the surface of the wire has a uniform thickness, and the outer circumferential surface of the cross section also forms a circle.

The tension control device of the present invention may be applied to a wire rod manufacturing apparatus that performs coating or coating treatment or other processing on the surface of the wire rod continuously supplied outside the manufacturing line of the unbonded PC strand of the above embodiment.

As described above, in the unbonded PC strand production apparatus equipped with the tension control device of the present invention, even if the loosening of the strands supplied from the supply table is not constant, even if vibration or shaking (or rocking) occurs, such vibrations may be generated. Strands that are attenuated or removed during the passage of the tension control device and move between the tension control device and the winder are moved linearly only in the direction of travel, so that the plastic coating process is performed smoothly and the winding failure is minimized. have.

Therefore, the present invention can improve the quality of the product through uniformity and appearance improvement of the plastic coating layer of the unbonded PC strand.

Claims (3)

In the unbonded PC strand production apparatus, the grease applicator and the plastic coating device are installed on the strand movement path between the feeder and the winder, so that the coating of grease is applied on the surface of the strand. The tension adjusting device 20 is installed in front of the stand, wherein the tension adjusting device 20 is a frame 21 standing on the strand W moving path and a roller vertically supported at the upper end of the frame 21. A roller group 23 composed of a bracket 22, a plurality of movable rollers 23a, 23a 'and fixed rollers 23b, 23b', 23b "mounted on the roller bracket 22; It is coupled to the roller conveying apparatus 24 (24 ') which makes raising and lowering of the movable rollers 23a and 23a', and the central axis 23b'a of any one of the said fixed rollers 23b '. Characterized in that it consists of an air brake device 25 for controlling the rotation of the roller Strand tension adjuster of eonbon Extended PC strand production line. 2. The roller conveying apparatus (24) (24 ') is configured to move up or down by rotation of the adjusting handles (24a) and 24'a mounted to the upper end of the roller bracket (22). It is characterized in that it is composed of a roller coupling tool (24c) (24'c) coupled to the lower portion of the conveying screw (24b) (24'b) and the movable roller 23a (23a ') to make the vertical conveyance Strand tension control device of the unbonded PC strand production line. 2. The air brake device (25) according to claim 1, wherein the air brake device (25) has a roller bracket (3) with a central axis (23b'a) of a roller (23b ') positioned in the middle of the fixed rollers (23b, 23b', 23b "). 22) an unbonded PC strand production line characterized in that a tension disc 25a is mounted at an extension end thereof and a disc brake pad 25b driven by pneumatic pressure is installed around one side of the tension disc. Strand tension control device.