WO2020234234A1

WO2020234234A1 - Method for manufacturing reinforcement meshes, and apparatus therefor

Info

Publication number: WO2020234234A1
Application number: PCT/EP2020/063801
Authority: WO
Inventors: Claus Brask; Kurt Offersen
Original assignee: Pedax Gmbh
Priority date: 2019-05-23
Filing date: 2020-05-18
Publication date: 2020-11-26
Also published as: DK201900629A8; EP3972752A1; EP3972752B1; DK180830B1; DK201900629A1; EP3972752C0

Abstract

The present invention relates to a method for manufacturing reinforcement meshes, and to an apparatus for use in such a method. The apparatus comprises an infeed unit, an infeed channel, a plurality of spinning stations, a plurality of positioning units, and a programmable control unit.

Description

Method for manufacturing reinforcement meshes, and apparatus therefor

Technical field of the invention

The present invention relates to a method for manufacturing reinforcement meshes, and to an apparatus for use in such a method.

Background of the invention

In attempts to reduce production costs in connection with reinforcement for civil works, particularly reinforcement for larger areas of concrete, such as decks, slabs or other elements, it is known in the art (e.g. W020081 19357 or

US7909067) to manufacture reinforcement nets or meshes, typically defining a mesh of reinforcement rods and wires. Such nets or meshes are easy to store and transport because they may be rolled up on a reel.

Nets for relatively small areas are needed for many types of applications, but the current manufacturing process of such nets does not allow for optimal utilization of the manufacturing machine's capacity. Another known problem is that the produced nets tend to be crooked rather than being straight.

It is an object of the present invention to solve the above-mentioned problems.

Description of the invention

One aspect relates to a method for making a reinforcement mesh for use in concrete structures, said mesh comprising reinforcement rods, which are held together by two wires to form a mesh comprising held rods at a desired mutual distance, the method comprising:

a) providing two wires each rolled up on their respective coils; b) inserting a reinforcement rod between said wires such that said two wires extend respectively above and below said reinforcement rod;

c) forming a spacer of said wires by twisting around said reinforcement rod in a first direction, thereby clamping said two wires around said reinforcement rod, which is thereby kept in the position, and continuing the twisting operation in said first direction until the desired length of said spacer has been achieved;

d) inserting a new reinforcement rod between said wires, such that said two wires extend respectively above and below said reinforcement rod;

wherein the method further comprises:

e) forming a spacer of said wires, said spacer comprising a twisting around said new reinforcement rod in the opposite direction relative to said first direction, which is thereby kept in the position, and such that said two wires are clamped around the individual rods, and continuing the twisting operation in said opposite direction until the desired length of said spacer has been achieved; and f) repeating steps d) and e) one or more times until the desired mesh length has been achieved;

wherein steps a)-f) are performed simultaneously at multiple sites along the length of the reinforcement rod.

By shifting the execution direction of the twisting operation, the formed reinforcement mesh is perfectly straight. It is thought that the spinning operation displaces the reinforcement rod a little bit in one direction. Hence, if the spinning operations are performed in alternating directions, the displacement is offset.

In one or more embodiments, the reinforcement rod is gradually moved away from the twisting point during the twisting operation.

In one or more embodiments, steps a)-e) are performed simultaneously at multiple sites along the length of each of a plurality of reinforcement rods positioned in continuation of each other. Thereby, reinforcement meshes wider than the individual reinforcement rods may be produced. Alternatively, a plurality of reinforcement meshes may be produced in line at the same time. In the latter situation, the reinforcement rods are positioned in continuation of each other and with a predetermined distance therebetween prior to performing steps c) and e).

In one or more embodiments, the positioning operation comprises the steps of:

- feeding a plurality of reinforcement rods to an infeed channel in communication with a plurality of spinning stations; the plurality of spinning stations being arranged in a side-by-side relationship, and positioned along one infeed channel; and

- positioning the plurality of reinforcement rods within the infeed channel to a predefined distance between one another along the longitudinal direction of the infeed channel; and wherein steps c) and e) further comprises:

- removing the fixed reinforcement rods from the infeed channel.

By using an infeed channel, it is secured that the reinforcement rods are positioned precisely in continuation of each other, and the preferred distance between them can be easily controlled.

In one or more embodiments, the positioning of the plurality of reinforcement rods within the infeed channel to a predefined distance between one another along the longitudinal direction of the infeed channel is performed by using a plurality of positioning units positioned along the infeed channel.

In the present context, the term“a plurality of” is to be understood as two or more units, such as three or more units.

In one or more embodiments, the positioning of the plurality of reinforcement rods within the infeed channel is performed with a positioning unit, preferably a plurality of positioning units.

In one or more embodiments, the positioning of the plurality of reinforcement rods into the infeed channel is performed manually. In one or more embodiments, the reinforcement rods positioned within the infeed channel are of different length and/or diameter and/or material property. Thus, the selection of reinforcement rods is chosen in order to provide reinforcement meshes having varying properties adapted for their end use.

In one or more embodiments, the amount and/or predefined distances between the reinforcement rods in a first cycle are different from the amount and/or predefined distances between the reinforcement rods in a second cycle.

A second aspect relates to a spinning station for performing the method according to the present invention, comprising:

- a rotatable shaft adapted for being driven by a drive unit;

- two wire coils mounted diametrically opposite each other on said rotatable shaft; and

- a wire guide secured to the shaft end opposite to the two wire coils; wherein the drive unit is configured to perform a wire spacer forming operation by rotating the rotatable shaft a pre-set period of time or a pre-set number of revolutions, and to change the rotatable shaft’s direction of rotation between a first and a second spacer forming operation.

In one or more embodiments, the wire guide comprises two brake units each adapted for controlling the roll-out of wire from each wire coil.

In one or more embodiments, each brake unit comprises:

- a first wire guide wheel; and

- a second wire guide wheel with a braking mechanism. Preferably, the wire guide wheels are provided with a guide track. The wire from the coil is first routed around the first guide wheel and then around the second guide wheel. The use of two guide wheels is to maintain the wire direction from the wire coils, but also provides a deformation resistance where the wire is bent and straightened again. In one or more embodiments, at least the second wire guide wheel is teethed or knurled in order to provide better grip on a reinforcement rod.

In one or more embodiments, the wire guide comprises two curved leaf springs each extending forward relative to the brake unit and each with a free end resiliently resting on one another or at least resiliently facing one another thereby defining a gap preferably being a few millimetres, such as 1 -20 mm, e.g. 1 -10 mm, preferably 1 -5 mm. This configuration forms a space between the leaf springs that is sized to receive a reinforcement rod perpendicularly to the leaf springs. The free end of each leaf spring comprises a wire guide channel adapted for receiving the wire exiting each brake unit. Thereby, the two wires are guided towards each other.

In one or more embodiments, the spinning station further comprises pulling means adapted for pulling in a reinforcement rod in a direction perpendicular to the length of the rod. In one or more embodiments, the pulling means are adapted to pull a reinforcement rod in a direction perpendicular to the length of the rod across the free ends of the leaf springs. Thereby said free ends are forced away from each other until the reinforcement rod has passed. The free ends will then, due to their resilient nature, return to their initial position.

A third aspect relates to an apparatus for use in the method according to the present invention, the apparatus comprising:

- an infeed unit;

- an infeed channel;

- a plurality of spinning stations in accordance with the present invention, arranged in a side-by-side relationship, and positioned along said infeed channel;

- a positioning unit positioned along said infeed channel; and

- a programmable control unit configured to control the activation of the positioning unit; wherein the programmable control unit, in response to a user input, is configured to activate the positioning unit to position a reinforcement rod within the infeed channel at a predefined position. In may be preferred to position multiple positioning units along the infeed channel. In this situation, the programmable control unit, in response to a user input, is configured to activate the positioning units to position a reinforcement rod within the infeed channel at a predefined position.

In one or more embodiments, the programmable control unit, in response to a user input, is configured to activate the positioning unit(s) to position a plurality of reinforcement rods within the infeed channel to a predefined distance between one another along the longitudinal direction of the infeed channel.

The positioning unit(s) may be configured as roll feeders, and more particularly as a pair of feed rolls. In one or more embodiments, the system further comprises a pair of feed rolls positioned at the entrance of the infeed channel. Preferably, two pairs of feed rolls are positioned at the entrance of the infeed channel, such as in the form of a linear feed drive. In one or more embodiments, the pair of feed rolls or the feed drive is configured to register when the backend of the reinforcement rod leaves a pair of feed rolls and to provide this information to the programmable control unit; wherein said programmable control unit uses this point in time and/or specific position of the backend of the reinforcement rod to activate one or more positioning units positioned along the infeed channel for a period of time corresponding to moving the reinforcement rod a predefined distance along the infeed channel. Preferably, it is the rear pair of feed rolls where the measurement is taking place, as the front pair of feed rolls thereby still hold onto the reinforcement rod during the measurement. One way of measuring when the backend leaves a pair of feed rolls may be by using an inductive sensor attached to the upper feed roll that uses the principle of electromagnetic induction to detect or measure the distance between the upper and the lower feed roll. The inductive sensor may then move relative to a magnetic plate mounted near the sensor, e.g. on the chassis of the lower feed roll. The specific position of the backend of the reinforcement rod within the infeed channel will always thereby be known. As the length of a reinforcement rod fed into the infeed channel is known by the programmable control unit, e.g. due to user input, it is possible for the programmable control unit to position the front end of a subsequent reinforcement rod entering the infeed channel a predefined distance from the backend of the previous reinforcement rod that has already been positioned within the infeed channel.

In one or more embodiments, the bottom of the infeed channel is configured for moving up and down. When the wire spacer forming operation has been terminated for a specific reinforcement rod, the programmable control unit may be configured to lower the bottom of the infeed channel to promote the release of the reinforcement rod therefrom, and configured to raise the bottom of the infeed channel again when said reinforcement rod has been removed, thereby making the infeed channel ready for receiving a new reinforcement rod. When the positioning unit(s) are configured as roll feeders, said roll feeders may be configured to open and close synchronously with up and down movement of the infeed channel. This operation may also be controlled by the programmable control unit.

Especially, but not exclusively, when the positioning unit(s) are configured as roll feeders there may be a slight error in the positioning operation when a

reinforcement rod has an uneven surface. This issue may not be problematic for positioning a single reinforcement rod within the infeed channel, but if more than one reinforcement rod needs to be positioned in line within the infeed channel with a predefined distance therebetween, the sum of positioning errors may be enough to cause problems. In order to solve this problem, the system may in one or more embodiments further comprise position determining means adapted for determining the position of the front end of the reinforcement rod positioned furthest inside the infeed channel. The position determining means may comprise blocking means, such as a plate or rod, pivotally extending into the infeed channel at predefined distance from the entrance of the infeed channel, preferably positioned at least halfway into the infeed channel, and more preferably positioned in the last 5-40% of the infeed channel. When the front end of a reinforcement rod moving within the infeed channel hits the blocking means, said blocking means tilts and signals to the programmable control unit. The programmable control unit may then be configured to use the time of activation and the position of the blocking means to activate one or more positioning units positioned along the infeed channel for a period of time corresponding to move the reinforcement rod back or forth a predefined distance along the infeed channel. The remaining distance needed to move the reinforcement rod will thereby be relatively short, thus reducing the risk of erroneous positioning.

It should be noted that embodiments and features described in the context of one of the aspects of the present invention also apply to the other aspects of the invention.

Brief description of the figures

Figure 1 shows a perspective view of an apparatus for manufacturing a reinforcement mesh in accordance with various embodiments of the invention;

Figure 2 is an enlarged view of a part of the apparatus shown in Figure 1 showing a spinning station and a positioning unit in accordance with various embodiments of the invention;

Figure 3 is an enlarged view of a part of the apparatus shown in Figure 1 showing a wire guide in accordance with various embodiments of the invention;

Figure 4 is an enlarged view of a part of the apparatus shown in Figure 1 showing an infeed unit in accordance with various embodiments of the invention; and

Figures 5-7 are enlarged views of a part of the apparatus shown in Figure 1 showing a position determining means in accordance with various embodiments of the invention.

Detailed description of the invention

Referring to Figure 1 , the general scheme of the invention is shown in

perspective view.

Figure 1 shows an apparatus 100 for manufacturing reinforcement meshes for reinforced concrete structures. The apparatus 100 comprises an infeed unit 200, an infeed channel 300, six spinning stations 400A-F, two positioning units 500A- B, and a programmable control unit 600. When a reinforcement rod is positioned in the infeed unit 200, the control unit 600, based on user input, activates the infeed unit 200 and the positioning units 500 to corporate in positioning the reinforcement rod at a preset position within the infeed channel 300. This process is continued until all reinforcement rods are positioned within the infeed channel 300. The control unit 600 then instruct the spinning stations 400 to fix the reinforcement rods with wire binders to form a mesh having the rods arranged at a predefined distance between one another along the longitudinal direction of the mesh. The infeed channel 300 then opens to release the reinforcement rods fixed in the mesh therefrom. A new cycle is then initiated.

The reinforcement meshes produced may be rolled up around itself at mesh rolling means (not shown) at a lower part of the spinning stations, such that the rods are kept essentially parallel, and such that the wire binders of the meshes form spiraling paths. The mesh rolling means may comprise a roll up chain system.

The six spinning stations 400A-F are arranged in a side-by-side relationship and positioned along the infeed channel 300. Flence, all spinning stations are fed from the same infeed channel 300. The six spinning stations 400A-F each (exemplified with spinning station 400A as shown in Figure 2) comprises a rotatable shaft 410 adapted for being driven by a drive unit 420, preferably a common drive unit; two wire coils 430 mounted diametrically opposite each other on said rotatable shaft 410; and a wire guide 450 secured to the shaft end opposite to the two wire coils 430. The drive unit 420 is configured to perform a wire spacer forming operation by rotating the rotatable shaft 410 a pre-set period of time or a pre-set number of revolutions, and to change the rotatable shaft’s 410 direction of rotation between a first and a second spacer forming operation.

In Figure 3, the wire guide 450 is shown comprising two brake units 452 each adapted for controlling the roll-out of wire from each wire coil 430. Each brake unit 452 comprises a first wire guide wheel 454, and a second wire guide wheel 456 with a braking mechanism. The wire guide wheels 454, 456 are each shown with a guide track 455, 457. The wire (not shown) from the coil is first routed around the first guide wheel 454 and then around the second guide wheel 456. The use of two guide wheels is to maintain the wire direction from the wire coils. The first 454 and second 456 guide wheels are mounted in a housing 458, and both housings for each brake unit are mounted on a common mounting plate 459 extending therefrom. A wire guide channel is formed through the mounting plate

459 and the housing 458 adapted for receiving the wire from the wire coil 430.

The wire guide 450 also comprises two curved leaf springs 460 each extending forward relative to the brake unit 452 and each with a free end 462 resiliently resting on one another, or at least resiliently facing one another thereby defining a gap preferably being a few millimetres, such as 1 -20 mm, e.g. 1 -10 mm, preferably 1 -5 mm. This configuration forms a space between the leaf springs

460 that is sized to receive a reinforcement rod perpendicularly to said leaf springs 460. The free end 462 of each leaf spring 460 comprises a wire guide channel 464 adapted for receiving the wire exiting each brake unit 452. Thereby, the two wires are guided towards each other. The bottom of the infeed channel 300 is configured for moving up and down. When the wire spacer forming operation has been terminated for a specific reinforcement rod, the programmable control unit is configured to lower the bottom of the infeed channel 300 to promote the release of the reinforcement rod therefrom, and configured to raise the bottom of the infeed channel 300 again when said reinforcement rod has been removed, thereby making the infeed channel ready for receiving a new reinforcement rod. The positioning units 500A, 500B are configured as roll feeders, and more particularly as a pair of feed rolls 510 (Figure 2). The roll feeders 510 are configured to open and close

synchronously with up and down movement of the infeed channel 300. This operation is also controlled by the programmable control unit 600.

The spinning station 400 further comprises pulling means 440 adapted for pulling in a reinforcement rod in a direction perpendicular to the length of the rod. The pulling means 440 are adapted to pull a reinforcement rod in a direction perpendicular to the length of the rod across the free ends 462 of the leaf springs 460. Thereby said free ends 462 are forced away from each other until the reinforcement rod has passed. The free ends 462 will then, due to their resilient nature, return to their initial position.

The infeed unit 200 (Figure 4) comprises two pairs of feed rolls 210A, 210B positioned at the entrance 310 of the infeed channel 300 in the form of a linear feed drive. The linear feed drive is configured to register when the backend of a reinforcement rod leaves a pair of feed rolls 210A, 210B and to provide this information to the programmable control unit 600. The programmable control unit uses this point in time and/or specific position of the backend of the

reinforcement rod to activate the positioning units 500 positioned along the infeed channel 300 for a period of time corresponding to moving the

reinforcement rod a predefined distance along the infeed channel 300.

The placement of a reinforcement rod into the infeed unit 200 may simply be performed by manually placing a reinforcement rod from a rod storage rack (not shown). However, reinforcement rods may alternatively be placed in the infeed unit 200 by an automatic feeding device (not shown) adapted for the purpose.

The rod storage rack may comprise shelves, e.g. for storing reinforcement rods having different properties with respect to length, diameter or material properties. Thus, reinforcement rods may be chosen in order to provide reinforcement meshes having varying properties adapted for their end use.

The programmable control unit 600 is configured to control the operation of the infeed unit 200, the positioning units 500, and the spinning stations 400.

The system shown also comprises a position determining means 700 adapted for determining the position of the front end of a reinforcement rod. The position determining means 700 comprises blocking means 710 (Figures 5-7) pivotally extending into the infeed channel 300 at a predefined distance from the entrance 310 of the infeed channel 300. When the blocking means 710 is tilted by the front end of a reinforcement rod (not shown) moving within the infeed channel 300, said blocking means 710 is configured signal this activation to the programmable control unit 600. The programmable control unit 600 is configured to use the time of activation and the position of the blocking means to activate the positioning units 500 positioned along the infeed channel 300 for a period of time

corresponding to move the reinforcement rod back or forth a predefined distance along the infeed channel 300.

Apart from the blocking means 710, the position determining means 700 comprises a sensor 720, such as an inductive sensor, configured for sensing when the blocking means 710 tilts. The blocking means 710 is connected to a pneumatic or hydraulic cylinder 730 adapted for returning the blocking means 710 to its un-tilted position. References

100 Apparatus for manufacturing reinforcement meshes

200 Infeed unit

210 Feed roll

300 Infeed channel

310 Entrance

400 Spinning station

410 Rotatable shaft

420 Drive unit

430 Wire coil

440 Pulling means

450 Wire guide

452 Brake unit

453 Wire guide channel

454 First wire guide wheel

455 Guide track

456 Second wire guide wheel

457 Guide track

458 Brake unit housing

459 Mounting plate

460 Leaf spring

462 Free end

464 Wire guide channel

500 Positioning unit

510 Feed roll

600 Control unit

700 Position determining means

710 Blocking means

720 Sensor

730 Pneumatic or hydraulic cylinder

Claims

1. A method for making a reinforcement mesh for use in concrete structures, said mesh comprising reinforcement rods, which are held together by two wires to form a mesh comprising held rods at a desired mutual distance, the method comprising:

a) providing two wires each rolled up on their respective coils;

b) inserting a reinforcement rod between said wires, such that said two wires extend respectively above and below said reinforcement rod;

characterized in that the method further comprises:

e) forming a spacer of said wires, said spacer comprising a twisting around said reinforcement rod in the opposite direction relative to said first direction, which is thereby kept in the position, and such that said two wires are clamped around the individual rods, and continuing the twisting operation in said opposite direction until the desired length of said spacer has been achieved; and f) repeating steps d) and e) one or more times until the desired mesh length has been achieved;

2. The method according to claim 1 , wherein steps a)-e) are performed simultaneously at multiple sites along the length of each of a plurality of reinforcement rods positioned in continuation of each other.

3. The method according to claim 2, wherein the plurality of reinforcement rods are positioned in continuation of each other and with a predetermined distance therebetween prior to performing steps a)-e).

4. The method according to claim 3, wherein the positioning operation comprises the steps of:

- feeding a plurality of reinforcement rods to an infeed channel (300) in

communication with a plurality of spinning stations (400); the plurality of spinning stations (400) being arranged in a side-by-side relationship, and positioned along one infeed channel (300); and

- positioning the plurality of reinforcement rods within the infeed channel (300) to a predefined distance between one another along the longitudinal direction of the infeed channel (300); and wherein steps c) and e) further comprises:

- removing the fixed reinforcement rods from the infeed channel (300).

5. The method according to claim 4, wherein the positioning of the plurality of reinforcement rods within the infeed channel (300) to a predefined distance between one another along the longitudinal direction of the infeed channel (300) is performed by using a plurality of positioning units (500) positioned along one infeed channel (300).

6. The method according to any one of the claims 1 -5, wherein the reinforcement rod is gradually moved away from the twisting point during the twisting operation.

7. The method according to any one of the claims 4-6, wherein the reinforcement rods positioned within the infeed channel (300) are of different length and/or diameter and/or material property.

8. A spinning station (400) for performing the method according to any one of the claims 1 -7, comprising:

- a rotatable shaft (410) adapted for being driven by a drive unit (420);

- two wire coils (430) mounted diametrically opposite each other on said rotatable shaft (410); and - a wire guide (450) secured to the shaft end opposite to the two wire coils (430); characterized in that the drive unit (420) is configured to perform a wire spacer forming operation by rotating the rotatable shaft (410) a pre-set period of time or a pre-set number of revolutions, and to change the rotatable shaft’s direction of rotation between a first and a second spacer forming operation.

9. The spinning station (400) according to claim 8, wherein the wire guide (450) comprises two brake units (452) each adapted for controlling the roll-out of wire from each wire coil (430).

10. The spinning station (400) according to claim 9, wherein each brake unit (452) comprises:

- a first wire guide wheel (454); and

- a second wire guide wheel (456) with a braking mechanism.

1 1. The spinning station (400) according to claim 10, wherein the wire guide wheels (454, 456) are provided with a guide track (455, 457).

12. The spinning station (400) according to claim 1 1 , wherein at least the second wire guide wheel (456) is teethed or knurled in order to provide better grip on a reinforcement rod.

13. The spinning station (400) according to any one of the claims 9-12, wherein the wire guide (450) comprises two curved leaf springs (460) each extending forward relative to the brake unit (452) and each with a free end resiliently resting on one another or at least resiliently facing one another, thereby defining a gap preferably being a few millimetres, such as 1 -20 mm.

14. The spinning station (400) according to any one of the claims 8-13, further comprising pulling means (440) adapted for pulling in a reinforcement rod in a direction perpendicular to the length of the rod.

15. The spinning station (400) according to claim 13 and 14, wherein said pulling means (440) are adapted to pull a reinforcement rod in a direction perpendicular to the length of the rod across the free ends of the leaf springs (460).

16. A system (100) for use in the method according to any one of the claims 1 -7, the apparatus (100) comprising:

- an infeed unit (200);

- an infeed channel (300);

- a plurality of spinning stations (400) in accordance with any one of the claims 8- 15, arranged in a side-by-side relationship, and positioned along said infeed channel (300);

- a positioning unit (500) positioned along said infeed channel (300); and

- a programmable control unit (600) configured to control the activation of the positioning unit (500);

wherein the programmable control unit (600), in response to a user input, is configured to activate the positioning unit (500) to position a reinforcement rod within the infeed channel (300) at a predefined position.

17. The system (100) according to claim 16, wherein the infeed unit (200) further comprises a pair of feed rolls (210) positioned at the entrance of the infeed channel (300); wherein the infeed unit (200) is configured to register when the backend of a fed reinforcement rod leaves said pair of feed rolls (210) and to provide this information to the programmable control unit (600); wherein said programmable control unit (600) uses this point in time and/or specific position of the backend of said reinforcement rod to activate a positioning unit (500) positioned along the infeed channel for a period of time corresponding to moving said reinforcement rod a predefined distance along said infeed channel (300).

18. The system (100) according to any one of the claims 16-17, further comprising a position determining means (700) adapted for determining the position of the front end of a reinforcement rod; wherein the position determining means (700) comprises blocking means (710) pivotally extending into the infeed channel (300) at a predefined distance from the entrance (310) of the infeed channel (300); wherein when the blocking means (710) is tilted by the front end of a reinforcement rod moving within the infeed channel (300), said blocking means (710) is configured signal this activation to the programmable control unit (600); wherein the programmable control unit (600) is configured to use the time of activation and the position of the blocking means (710) to activate one or more positioning units (500) positioned along the infeed channel (300) for a period of time corresponding to move the reinforcement rod back or forth a predefined distance along the infeed channel (300).