SE1951228A1 - Rebar tying device comprising a wire locking mechanism and a control unit for controlling the wire locking mechanism - Google Patents

Abstract

A wire locking mechanism for a reinforcement bar, rebar, wire tying device, the locking mechanism comprising a holding member and a counter-holding member arranged to engage respective and opposite sides of a wire to releasably hold the wire in a locking position, where a holding force exerted on the wire by the holding member is normal to a holding plane, wherein the holding member is supported on a first end of an excentre arm, the excentre arm being rotatably supported on a first shaft to rotate about an excentre arm center of rotation, wherein the holding member is arranged distanced along a first axis from the excentre arm center of rotation, the first axis forming an acute angle with the holding plane when in the locking position.

Description

TITLE A REBAR WIRE TYING DEVICE TECHNICAL FIELD The present disclosure relates to wire tying devices for tying reinforcementbars (rebars) together to form a rebar structure for reinforcing, e.g., concreteand other solidifiable materials.

BACKGROUND Concrete is strong under compression but often has relatively weak tensilestrength. Reinforcing bars, or rebars, are therefore often used to strengthenconcrete structures, where they significantly increase the tensile strength of the concrete.

The most common type of rebar is carbon steel, typically consisting of hot-rolled round bars with deformation patterns. Other readily available typesinclude stainless steel, and composite bars made of glass fibre, carbon fibre,or basalt fibre. The steel reinforcing bars may also be coated in an epoxy resindesigned to resist the effects of corrosion mostly in saltwater environments,but also in land-based constructions.

The rebar elements are normally connected into a rebar structure or lattice bytying the elements together with steel wire. For tying epoxy coated orgalvanised rebars, epoxy coated, or galvanized wire is normally used. The wiremay also be coated in plastic or the like to prevent corrosion.

Due to the large number of connection points between rebar elements in a larger rebar structure, it is desired to automate the wire tying.

EP 2666932 B1 discloses an automatic wire tying device for tying rebarstogether. lt is important that the rebars are firmly connected together and that the wire knots are taut. Achieving a sufficiently tight knot may be a problem when using automatic wire tying devices, especially if the wire is slippery due to, e.g.,water, ice and/or oil on the wire. A further problem relates to if the wire has anuneven thickness that varies along the wire length, since this complicates, e.g., calibrating an automatic wire tying device locking mechanism.

There is a need for improved automatic rebar wire tying devices.

SUMMARY lt is an object of the present disclosure to provide improved automatic rebarwire tying devices. This object is at least in part obtained by a wire lockingmechanism for a rebar wire tying device. The locking mechanism comprises aholding member and a counter-holding member arranged to receive a free endof a wire and to engage respective sides of the wire to releasably hold the wirein a locking position, where a holding force exerted on the wire by the holdingmember is normal to a holding plane. The holding member is supported on afirst end of an excentre arm. The excentre arm is rotatably supported on a firstshaft to rotate about an excentre arm center of rotation, wherein the holdingmember is arranged distanced along a first axis from the excentre arm centerof rotation, the first axis forming an acute angle with the holding plane when inthe locking position, wherein at least one of the holding member (210, 310)and the counter-holding member (220, 330) comprises a rotatably supported toothed wheel.

This way even slippery wires are held firmly during knot formation. Theexcentre arm arrangement provides for an increased holding as the wire ispulled out from the locking mechanism. The wire can, however, be released ina controlled manner by separating the holding member from the counter-holding member.

According to aspects, the holding member comprises a first toothed wheelrotatably supported on a second shaft, and a catch arrangement configured tolock the first toothed wheel when in the locking position. Thus, the wire can be released in a precise manner, and there is a limited amount of build-up of wire shavings as the wire is released, since the wire does not shave against, e.g.,a holding pad or the like.

According to aspects, the first toothed wheel comprises teeth with acircumferentially blunt and/or essentially flat portion configured to engage thewire when in the locking position. The circumferentially blunt and/or essentiallyflat portion reduces the risk of the wire braking during knot formation when thewire is held by the locking mechanism, since a blunt tooth does not cut into the wire in the way a more sharp tooth would.

According to aspects, the counter-holding member comprises a secondtoothed wheel rotatably supported on a third shaft. The teeth on the secondtoothed wheel increases the ability of the mechanism to hold on to wires ofvarying thickness. The acute angle can also be formed more aggressively dueto the teeth on the second toothed wheel, since now two wheels with teethhold the wire in the locked position. The second toothed wheel further reducesbuild-up of wire shavings.

According to aspects, the wire locking mechanism comprises a first actuatorarranged to rotate the excentre arm about the excentre arm center of rotationin a first direction to separate the holding member from the counter-holdingmember when in a wire-infeed mode. This way the wire can more easily enterinto locking contact with the holding member and the counter-holding member, thereby simplifying the tying operation.

According to aspects, the wire locking mechanism comprises a secondactuator arranged to rotate the excentre arm about the excentre arm center ofrotation in a second direction opposite to the first direction to move the holdingmember into the locking position. The second actuator allows for efficientcontrol of the mechanism, in particular, the mechanism can be placed inlocking position by means of the second actuator.

According to aspects, the first actuator and/or the second actuator comprisesa solenoid device. A solenoid device is a cost-effective control means whichcan be controlled electrically by, e.g., a control unit.

According to aspects, the excentre arm and the counter-holding member aresupported on a joining member, wherein the joining member is rotatablysupported on a fourth shaft to rotate in relation to a locking mechanism bodyin response to a pull force acting on the wire. This way the resulting knot onthe wire becomes tighter, since the locking mechanism is able to align with apull force acting on the wire during the knot tying operation, thereby minimizingany bends on the wire which contribute negatively to knot tightness.

According to aspects, the wire locking mechanism also comprises a controlarm arrangement. The control arm arrangement comprises an engagementsurface for engaging a cylinder cam, whereby, upon rotation of the lockingmechanism body to a pre-determined angle, the control arm arrangement isconfigured to release the catch arrangement, thereby placing the first toothedwheel in a free rolling condition and releasing the wire from the wire lockingmechanism. The control arm arrangement with the cylinder cam allows for avery precise timing of the release operation. This precise timing simplifies knotformation and reduces risk of the wire braking when tying the knot. The precisetiming allows for forming tight knots with minimum slack, which is an advantage.

According to aspects, the engagement surface for engaging the cylinder camcomprises a cylindrical roller configured to traverse the cylinder cam. The roller reduces friction, which is an advantage.

There are also disclosed herein wire tying devices and control units associated with the above mentioned advantages.

Generally, all terms used in the claims are to be interpreted according to theirordinary meaning in the technical field, unless explicitly defined otherwiseherein. All references to "a/an/the element, apparatus, component, means,step, etc." are to be interpreted openly as referring to at least one instance ofthe element, apparatus, component, means, step, etc., unless explicitly statedotherwise. The steps of any method disclosed herein do not have to beperformed in the exact order disclosed, unless explicitly stated. Further features of, and advantages with, the present invention will become apparent when studying the appended claims and the following description. The skilledperson realizes that different features of the present invention may becombined to create embodiments other than those described in the following, without departing from the scope of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The present disclosure will now be described in more detail with reference tothe appended drawings, where Figure 1 shows an example wire tying device; Figure 2 schematically illustrates a wire locking mechanism; Figures 3-4 illustrate details of example wire locking mechanisms; Figure 5 schematically illustrates a rotatable wire locking mechanism; Figure 6 illustrates an example rotatable wire locking mechanism; Figure 7 shows an example wire locking mechanism assembled with a body;Figure 8 is a flow chart illustrating methods; Figure 9 shows an example locking mechanism in neutral position; Figure 10 shows an example locking mechanism in wire infeed mode;Figure 11 shows an example locking mechanism in wire locking mode; and Figure 12 shows an example locking mechanism during wire tensioning.

DETAILED DESCRIPTION The invention will now be described more fully hereinafter with reference to theaccompanying drawings, in which certain aspects of the invention are shown.This invention may, however, be embodied in many different forms and shouldnot be construed as limited to the embodiments and aspects set forth herein;rather, these embodiments are provided by way of example so that thisdisclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elementsthroughout the description. lt is to be understood that the present invention is not limited to theembodiments described herein and i||ustrated in the drawings; rather, theskilled person will recognize that many changes and modifications may bemade within the scope of the appended claims.

Figure 1 shows a wire tying device 100 for tying wire knots that secure a rebarstructure. The wire tying device is arranged to feed 110 a free end of a wireout from an opening in a tying head 101 of the device. The wire is ro||ed priorto being fed out from the wire tying head 101, and therefore assumes anarcuate form due to the ro||ing inside the tying head 101. EP 2666932discusses ro||ing wire such that it extends in an arcuate form when exiting awire tying head. Rolling arrangements for ro||ing rebar tying wire will thereforenot be discussed in more detail herein.

Herein, the wire has a free end. This is the end of the wire which is feed outfrom the tying head 101 and then received back in the tying head.

The wire extends along an arcuate path to encircle the rebars (not shown inFigure 1) which are to be tied together and is then received 120 back in thetying head 101, where it is held by a wire locking mechanism which will bediscussed in detail below.

The wire locking mechanism body comprised in the wire tying head 101 is thenbrought to rotate 130 about a wire tying head axis H, which rotation forms aknot on the wire. The wire tying device 100 is also arranged to cut the wire.

The whole process is automatically executed in sequence when the wire tyingdevice is triggered by an operator using a trigger 140. A length of wire is storedon a spool 150 comprised in a spool compartment 160 of the wire tying device.Thus, the wire tying device 100 allows for conveniently an efficiently tyingtogether rebar structures.

A problem when tying rebars together is that the wire sometimes is hard tohold fixedly by the wire locking mechanism during formation of the knot. The wire may, e.g., be slick from oil, water, ice and the like, causing it to slip in theIocking mechanism. Such slipping often results in a loose knot, which is notdesired since too many loose knots lead to a non-rigidly assembledreinforcement structure. Also, slipping wires tend to cause build-up of wireparticles inside the wire tying head, since the slipping wire shaves or isabraded by the Iocking mechanism as it slips.

Also, the wire must be released at the exact right time in the tying process,since otherwise the wire may brake at the wrong time, causing a failed knot.This is because tension forces in the wire increases during rotation 130 of thewire tying head. lt may be a problem to achieve sufficient release timing accuracy.

Figure 2 illustrates a wire Iocking mechanism 200 for a rebar wire tying devicesuch as the device 100. The Iocking mechanism comprises a holding member210 and a counter-holding member 220 arranged to receive a free end of awire 230 and to engage respective sides of the wire 230 to releasably hold thewire in a Iocking position. Normally, the holding member 210 and the counter-holding member 220 are arranged to engage opposite sides of the wire 230,but this is not necessary as the holding member may engage the wire at anangle with respect to the counter-holding member.

To hold the wire 230 in Iocking position means that the wire is able to resist apull force F2, pulling the wire out from the wire tying head, without significantslipping. The pull force F2 on the wire is generated, e.g., by running the wirefeed mechanism of the wire tying device 100 in reverse.

A holding force F1 exerted on the wire 230 by the holding member 210 isnormal to a holding plane A2 extending between holding surfaces 211, 221 ofthe holding member and the counter-holding member.

To releasably hold the wire means that the holding force can be reduced at apre-determined time instant during the tying process, whereby the wire is released from the wire Iocking mechanism.

Optionally, the holding surfaces 211, 221 of any of the holding and/or counter- holding member comprises friction increasing means such as serrations or resilient coatings, e.g., rubber coating. The holding member 210 and/or thecounter-holding member 220 may be arranged as toothed wheels, which willbe discussed in detail below.

The holding member 210 is supported on a first end of an excentre arm 240.The excentre arm 240 is rotatably supported on a first shaft 250 to rotate indirection R1 about an excentre arm center of rotation 255. The holding member210 is arranged distanced D along a first axis A1 from the excentre arm centerof rotation 255. This means that the holding force F1 develops as the excentrearm 240 is rotated about the excentre arm center of rotation 255 in counter-clockwise direction when viewed as in Figure 2. The first axis A1 forms anacute angle A with the holding plane A2 when in the locking position.

The excentre arm 240 together with the holding member 210 and the counter-holding member 220 form an excentre locking mechanism which holds the wirein response to the pull force F2. lf the pull force F2 increases, then the frictionbetween the wire 230 and the holding member causes the excentre are 240 towant to rotate in direction R1 shown in Figure 2. This moment results in anincreased holding force F1. Thus, the harder the wire is pulled -the more firmlyit is held by the wire locking mechanism. Also, a reduced pull force F2 resultsin a reduced holding force F1. The wire locking mechanism can be opened,and the wire released, by rotating the excentre arm clockwise about the excentre arm center of rotation 255, i.e., in a direction opposite to direction R1.

At least one of the holding member 210 and the counter-holding member 220comprises a rotatably supported toothed wheel (illustrated in Figure 2 bydashed circles). This at least one toothed wheel allows for holding wires ofvarying dimension, and also allows for releasing the wire without shaving material off from the wire, due to the rotation of the wheel. ln case only one of the holding member 210 and the counter-holding member220 comprises a rotatably supported toothed wheel, the other may comprise,e.g., a supporting surface or the like. A holding member 210 not comprising arotatably supported toothed wheel may be integrally formed with the excentrearm 240, i.e., a portion of the excentre arm 240.

Figure 3 shows an example embodiment of the wire locking mechanism 300.The holding member here comprises a first toothed wheel 310 rotatablysupported on a second shaft 313, and a catch arrangement 312 configured tolock the first toothed wheel when in the locking position. The catcharrangement 312 is supported on the excentre arm 340 and therefore rotatestogether with the first toothed wheel 310.

According to aspects, the counter-holding member 320 comprises a secondtoothed wheel rotatably supported on a third shaft 323. However, it isappreciated that the counter-holding member 320 may also comprise, e.g., aheel, block, or other fixed support.

The catch arrangement can of course also be configured to lock the secondtoothed wheel 320 instead of the first toothed wheel 310. There may also beone catch arrangement arranged per toothed wheel.

The teeth on the second toothed wheel increases the ability of the mechanismto hold on to wires of varying thickness along the wire length. The angle A,shown in, e.g., Figure 1, can be formed more aggressively due to the teeth onthe second toothed wheel, since now two wheels with teeth hold the wire inthe locked position.

With reference to Figure 3, an opening between the holding member 310 andthe counter-holding member 320 can be created by rotating the excentre arm340 in a direction opposite to the rotation direction R1. The wire 230 can thenbe received between the holding member and the counter-holding member more easily.

Optionally, the catch arrangement 312 is spring loaded towards a position tolock the first toothed wheel.

The second toothed wheel 320 making up the counter-holding member maybe free-rolling, but as long as the catch arrangement 312 is in locking contactwith the first toothed wheel 310, and the wire 230 contacts both the first andthe second toothed wheel, the locking mechanism 300 is in locking position. Aholding force F1 will develop in response to a pull force F2 on the wire to holdthe wire firmly even if the wire is slippery due to, e.g., oil or ice.

According to aspects, the first toothed wheel 310 comprises teeth with acircumferentially blunt and/or essentially flat portion 311 configured to engagethe wire 230 when in the locking position. The blunt portions spare the wirefrom the cutting or shearing force exerted by the teeth on the toothed wheelon the wire when the holding force F1 is developed.

According to some aspects, the length of the teeth on the second wheel 320is set in dependence of the wire thickness so as to not accidentally cut the wireby the holding force F1.

The different components of the wire locking mechanism may be spring loadedso as to be biased towards respective default positions. The spring biasingmay be achieved using, e.g., torsion springs. For instance, the excentre arm240, 340 may be spring loaded towards the locking position and the catcharrangement 312 may be spring loaded towards a locking contact with the firsttoothed wheel 310.

Alternatively, or in combination, the catch arrangement may be spring loadedtowards a locking contact with the second toothed wheel 320. lt is againappreciated that any of the first and second toothed wheel, or both, can bearranged to be locked by a catch arrangement. There may be one, two, ormore catch arrangements configured to lock toothed wheels when in thelocking position. ln general, to operate the wire locking mechanisms 200, 300, the wire lockingmechanism optionally comprises a first actuator arranged to rotate theexcentre arm 240, 340 about the excentre arm center of rotation 255, 355 in afirst direction (opposite to direction R1 in Figures 2 and 3) to separate theholding member 210, 310 from the counter-holding member 220, 320 when in a wire-infeed mode.

The wire locking mechanisms 200, 300 optionally also comprise a secondactuator arranged to rotate the excentre arm 240, 340 about the excentre armcenter of rotation 255, 355 in a second direction R1 opposite to the firstdirection to move the holding member 210, 310 into the locking position. 11 The first actuator and/or the second actuator may, e.g., comprise respectivesolenoid devices configured to exert forces F3, F4 on the excentre arm. EP2666932 B1 discusses such actuators. However, other actuators, such asactuators based on magnetic force, may also be used to control the wire Iocking mechanism.

A control arm arrangement 360 shown in Figure 3 may be used to both engageand release the catch arrangement 312, as will be discussed in more detailbelow in connection to Figures 9-12. The control arm arrangement 360 mayalso be used to force the excentre arm 340 to rotate in direction R1 towardsthe Iocking position. A solenoid device may be used to push onto the control arm arrangement, i.e., to exert a force F4. lt is, as noted above, preferred to release the wire from the wire Iockingmechanism with accurate timing so as to not break the wire during the tyingoperation. Figure 4 shows details of a wire Iocking mechanism 400 whichcomprises a control arm arrangement 360. The control arm arrangement 360comprises an engagement surface 410 for engaging a cylinder cam 420,whereby, upon rotation of the Iocking mechanism body 530 (shown in Figure7) to a pre-determined angle. The control arm arrangement 360 is configuredto release the catch arrangement 312, thereby placing the first toothed wheel310 in a free rolling condition and releasing the wire 230 from the wire Iocking mechanism.

With reference to Figures 4 and 7, the cylinder cam 420 allows for a precisecontrol of the release of the wire Iocking mechanism 400. By varying the camwidth W1, W2, the pushing force F4 on the control arm arrangement 360 canbe accurately synchronized with a rotation of the Iocking mechanism bodyduring tying operation. The Iocking mechanism body 530 starts in a positionwhere the cam width W1 is relatively small and therefore exerts no force 411on the control arm arrangement 360. As the Iocking mechanism body rotates,the width increases up to a width W2, and the control arm arrangement thenmoves in direction of the catch arrangement 312 to release the catch, therebyreleasing the first toothed wheel 310. 12 lt is an advantage that the first and second toothed wheels are in free rollingcondition as the wire is released, since this minimizes abrasion by the holdingmembers on the wire 230, thereby preventing build-up of wire particles insidethe wire tying head 101.

According to some aspects, the engagement surface 410 for engaging thecylinder cam 420 comprises a cy|indrica| roller configured to traverse thecylinder cam 420. The roller reduces friction and therefore provides for asmoother knot tying operation. ln other words, the control arm arrangement360 comprises an engagement surface 410, which may be a roller bearing.The control arm 360 is pivotably arranged about an axis 361. lt is important that the wire 230 is not subject to an unnatural arcuate formduring the tying operation, as this may result in a loose knot. With reference toFigure 3, such an arcuate form may result if the pull force F2 on the wire 230is not aligned with the holding plane A2. With reference to Figure 5; To reducethis effect, the wire locking mechanism may be arranged rotatable with respectto the locking mechanism body 530. This way, the whole locking mechanismwill respond to a pull force on the wire by rotating R2 the holding plane A2 tobe more aligned with the direction of a pull force F2. The wire lockingmechanism may be spring-loaded towards a default position for receiving the wire.

Having this in mind, Figures 5 and 6 schematically illustrate a wire lockingmechanism 500, 600 according to some aspects of the present disclosure. Theexcentre arm 340 and the counter-holding member 320 are supported on ajoining member 510, 610, wherein the joining member 510, 610 is rotatablysupported on a fourth shaft 520, 620 to rotate in relation to a lockingmechanism body 530 in response to a pull force F2 acting on the wire 230. ltis appreciated that this rotating feature is applicable also to the more generallocking mechanism 200 illustrated in Figure 2.

Figure 8 is a flow chart illustrating a method and a control unit 800 configuredto perform the method. The control unit 800 is configured to control a wire 13 Iocking mechanism 200, 300, 400, 500, 600, 700 for a rebar wire tying device100.

With reference to Figures 9-12, the control unit is configured to transition S1the wire Iocking mechanism from a neutral position P1 into a wire infeed modeposition P2. As discussed above, the wire Iocking mechanism may be spring-loaded or otherwise biased towards a neutral position P1 shown in Figure 9where the excentre arm 340 is rotated to separate the holding member 310from the counter-holding member 320, and the catch arrangement is in Iockingcontact with the first toothed wheel.

The control unit then controls S2 wire feed by the wire tying device 100 toreceive a wire 230 in the wire Iocking mechanism 200, 300, 400, 500, 600,700. The wire is rolled prior to exiting the wire tying head, and thereforeencircles the rebars to be tied together. Figure 10 illustrates the wire Iockingmechanism in wire-infeed mode P2. The excentre arm 340 is rotated by meansof, e.g., a solenoid device acting on a link arm 710 to generate the force F3.Note that the catch arrangement 312 is released when the Iocking mechanismis in the wire-infeed mode P2. This release can be achieved, e.g., by meansof the control arm 360 discussed above. The wire 230 is able to enter betweenthe holding member 310 and the counter-holding member 320 easily due tothe free-rolling state of the toothed wheels in the wire-infeed mode P2.

The control unit then transitions S3 the wire Iocking mechanism from the wireinfeed mode P2 into a Iocking position P3, where the wire is held between theholding member 310 and the counter-holding member 320. To transition theIocking mechanism into the Iocking position P3, the excentre arm 340 iscaused to rotate in direction R1 by means of, e.g., the solenoid device and thecontrol arm discussed above.

The Iocking mechanism then rotates in direction R2 in response to a pull forceon the wire 230. The pull force on the wire is generated by running the wirefeed mechanism of the wire tying device in reverse. This rotation helps ensurethat the knot is tight. 14 Figure 12 shows a Iocking mechanism in rotated mode P4, after rotating indirection R2. The first axis A1 after rotation is denoted A1' and the holding plane after rotation is denoted A2”.

The control unit then rotates S4 130 the Iocking mechanism body 530 to tie aknot on the wire 230 and, at a pre-determined angle of rotation, the wire is released S5 from the wire Iocking mechanism.

Many of the features disclosed above may be implemented independently fromeach other. For instance, with reference mainly to Figures 5 and 6, there isalso disclosed herein a wire Iocking mechanism 500, 600 for a reinforcementbar, rebar, wire tying device 100, the Iocking mechanism comprising a holdingmember 210, 310 and a counter-holding member 220, 320 arranged to engagerespective and opposite sides of a wire 230 to releasably hold the wire in aIocking position, where a holding force F1 exerted on the wire 230 by theholding member 210, 310 is normal to a holding plane A2, wherein the holdingmember 210, 310 is supported on a first end of an excentre arm 240, 340, theexcentre arm 240, 340 being rotatably supported on a first shaft 250, 350 torotate R1 about an excentre arm center of rotation 255, 355, wherein theholding member 210, 310 is arranged distanced D along a first axis A1 fromthe excentre arm center of rotation 255, 355, the first axis A1 forming an acuteangle A with the holding plane A2 when in the Iocking position, wherein theexcentre arm 240, 340 and the counter-holding member 220, 320 aresupported on a joining member 510, 610, wherein the joining member 510,610 is rotatably supported on a fourth shaft 520, 620 to rotate in relation to aIocking mechanism body 530 in response to a pull force F2 acting on the wire230.

With reference mainly to Figures 5 and 6, there is furthermore disclosed hereina wire Iocking mechanism 400, 700 for a reinforcement bar, rebar, wire tyingdevice 100, the Iocking mechanism comprising a holding member 210, 310and a counter-holding member 220, 320 arranged to engage respective andopposite sides of a wire 230 to releasably hold the wire in a Iocking position,where a holding force F1 exerted on the wire 230 by the holding member 210, 310 is normal to a holding plane A2, wherein the holding member 210, 310 issupported on a first end of an excentre arm 240, 340, the excentre arm 240,340 being rotatably supported on a first shaft 250, 350 to rotate R1 about anexcentre arm center of rotation 255, 355, wherein the holding member 210,310 is arranged distanced D along a first axis A1 from the excentre arm centerof rotation 255, 355, the first axis A1 forming an acute angle A with the holdingplane A2 when in the locking position, the wire locking mechanism 300, 400,600, 700 further comprising a control arm arrangement 360, the control armarrangement 360 comprising an engagement surface 410 for engaging acylinder cam 420, whereby, upon rotation of the locking mechanism body 530to a pre-determined angle, the control arm arrangement 360 is configured torelease the wire 230 from the wire locking mechanism 400, 700.

Other example features disclosed above which may be implementedindependently from each other comprise a wire locking mechanism 200, 300,400, 500, 600, 700 for a reinforcement bar, rebar, wire tying device 100, thelocking mechanism comprising a holding member 210, 310 and a counter-holding member 220, 320 arranged to engage respective sides of a wire 230to releasably hold the wire in a locking position, wherein the holding member210, 310 and the counter-holding member 220, 320 are supported on a joiningmember 510, 610, wherein thejoining member 510, 610 is rotatably supportedon a fourth shaft 520, 620 to rotate in relation to a locking mechanism body530 in response to a pull force F2 acting on the wire 230.

According to aspects, a holding force F1 exerted on the wire 230 by the holdingmember 210, 310 is normal to a holding plane A2, wherein the holding member210, 310 is supported on a first end of an excentre arm 240, 340, the excentrearm 240, 340 being rotatably supported on a first shaft 250, 350 to rotate R1about an excentre arm center of rotation 255, 355, wherein the holdingmember 210, 310 is arranged distanced D along a first axis A1 from theexcentre arm center of rotation 255, 355, the first axis A1 forming an acuteangle A with the holding plane A2 when in the locking position. 16 According to aspects, the holding member 310 comprises a first toothed wheelsupported on a second shaft 313, and a catch arrangement 312 configured tolock the first toothed wheel when in the locking position.

According to aspects, the catch arrangement 312 is spring loaded towards aposition to lock the first toothed wheel.

According to aspects, the first toothed wheel comprises teeth with acircumferentially blunt and/or essentially flat portion 311 configured to engagethe wire 230 when in the locking position.

According to aspects, the counter-holding member 320 comprises a secondtoothed wheel rotatably supported on a third shaft 323.

According to aspects, the excentre arm 240, 340 is spring loaded towards thelocking position.

According to aspects, the wire locking mechanism comprises a first actuatorarranged to rotate the excentre arm 240, 340 about the excentre arm center ofrotation 255, 355 in a first direction to separate the holding member 210, 310from the counter-holding member 220, 320 when in a wire-infeed mode.

According to aspects, the wire locking mechanism comprises a secondactuator arranged to rotate the excentre arm 240, 340 about the excentre armcenter of rotation 255, 355 in a second direction opposite to the first directionto move the holding member 210, 310 into the locking position.

According to aspects, the excentre arm 240, 340 and the counter-holdingmember 220, 320 are supported on a joining member 510, 610, wherein thejoining member 510, 610 is rotatably supported on a fourth shaft 520, 620 torotate in relation to a locking mechanism body 530 in response to a pull forceF2 acting on the wire 230.

According to aspects, the wire locking mechanism comprises a control arm arrangement 360, the control arm arrangement 360 comprising anengagement surface 410 for engaging a cylinder cam 420, whereby, uponrotation of the locking mechanism body 530 to a pre-determined angle, the control arm arrangement 360 is configured to release the catch arrangement 17 312, thereby placing the first toothed wheel 310 in a free rolling condition andreleasing the wire 230 from the wire Iocking mechanism.

According to aspects, the engagement surface 410 for engaging the cylindercam 420 comprises a cylindrical roller configured to traverse the cylinder cam420.

According to aspects, the wire Iocking mechanism 300, 400, 600, 700comprises a catch arrangement configured to lock the second toothed wheelwhen in the Iocking position.

There is also disclosed herein a wire Iocking mechanism 200, 300, 400, 500,600, 700 for a reinforcement bar, rebar, wire tying device 100, the Iockingmechanism comprising a holding member 210, 310 and a counter-holdingmember 220, 320 arranged to engage respective sides of a wire 230 toreleasably hold the wire in a Iocking position, wherein the holding member 310comprises a first toothed wheel supported on a second shaft 313, and a catcharrangement 312 configured to lock the first toothed wheel when in the Iockingposition, the Iocking mechanism further comprising a control arm arrangement360, the control arm arrangement 360 comprising an engagement surface 410for engaging a cylinder cam 420, whereby, upon rotation of the Iockingmechanism body 530 to a pre-determined angle, the control arm arrangement360 is configured to release the catch arrangement 312, thereby placing thefirst toothed wheel 310 in a free rolling condition and releasing the wire 230 from the wire Iocking mechanism.

According to aspects, the engagement surface 410 for engaging the cylindercam 420 comprises a cylindrical roller configured to traverse the cylinder cam420.

According to aspects, a holding force F1 exerted on the wire 230 by the holdingmember 210, 310 is normal to a holding plane A2, wherein the holding member210, 310 is supported on a first end of an excentre arm 240, 340, the excentrearm 240, 340 being rotatably supported on a first shaft 250, 350 to rotate R1about an excentre arm center of rotation 255, 355, wherein the holdingmember 210, 310 is arranged distanced D along a first axis A1 from the 18 excentre arm center of rotation 255, 355, the first axis A1 forming an acuteangle A with the holding plane A2 when in the Iocking position.

According to aspects, the catch arrangement 312 is spring loaded towards a position to lock the first toothed wheel.

According to aspects, the first toothed wheel comprises teeth with acircumferentially blunt and/or essentially flat portion 311 configured to engagethe wire 230 when in the Iocking position.

According to aspects, the counter-holding member 320 comprises a second toothed wheel rotatably supported on a third shaft 323.

According to aspects, the excentre arm 240, 340 is spring loaded towards the Iocking position.

According to aspects, the wire Iocking mechanism comprises a first actuatorarranged to rotate the excentre arm 240, 340 about the excentre arm center ofrotation 255, 355 in a first direction to separate the holding member 210, 310from the counter-holding member 220, 320 when in a wire-infeed mode.

According to aspects, the wire Iocking mechanism comprises a secondactuator arranged to rotate the excentre arm 240, 340 about the excentre armcenter of rotation 255, 355 in a second direction opposite to the first directionto move the holding member 210, 310 into the Iocking position.

According to aspects, the excentre arm 240, 340 and the counter-holdingmember 220, 320 are supported on a joining member 510, 610, wherein thejoining member 510, 610 is rotatably supported on a fourth shaft 520, 620 torotate in relation to a Iocking mechanism body 530 in response to a pull forceF2 acting on the wire 230.

According to aspects, the wire Iocking mechanism comprises a catcharrangement configured to lock the second toothed wheel when in the Iocking position.

Claims (19)

1. A wire Iocking mechanism (200, 300, 400, 500, 600, 700) for areinforcement bar, rebar, wire tying device (100), the Iocking mechanismcomprising a holding member (210, 310) and a counter-holding member (220,320) arranged to receive a free end of a wire (230) and to engage respectivesides of the wire (230) to releasably hold the wire in a Iocking position, wherea holding force (F1) exerted on the wire (230) by the holding member (210,310) is normal to a holding plane (A2), wherein the holding member (210, 310)is supported on a first end of an excentre arm (240, 340), the excentre arm(240, 340) being rotatably supported on a first shaft (250, 350) to rotate (R1)about an excentre arm center of rotation (255, 355), wherein the holdingmember (210, 310) is arranged distanced (D) along a first axis (A1) from theexcentre arm center of rotation (255, 355), the first axis (A1) forming an acuteangle (A) with the holding plane (A2) when in the Iocking position, wherein atleast one of the holding member (210, 310) and the counter-holding member(220, 330) comprises a rotatably supported toothed wheel.

2. The wire Iocking mechanism (300, 400, 600, 700) according to claim 1,wherein the holding member (310) comprises a first toothed wheel rotatablysupported on a second shaft (313), and a catch arrangement (312) configuredto lock the first toothed wheel when in the Iocking position.

3. The wire Iocking mechanism (300, 400, 600, 700) according to claim 2,wherein the catch arrangement (312) is spring loaded towards a position tolock the first toothed wheel.

4. The wire Iocking mechanism (300, 400, 600, 700) according to claim 2 or3, wherein the first toothed wheel comprises teeth with a circumferentially bluntand/or essentially flat portion (311) configured to engage the wire (230) whenin the Iocking position.

5. The wire Iocking mechanism (300, 400, 600, 700) according to any ofclaims 2-4, wherein the counter-holding member (320) comprises a secondtoothed wheel rotatably supported on a third shaft (323).

6. The wire Iocking mechanism (200, 300, 400, 500, 600, 700) according toany previous claim, wherein the excentre arm (240, 340) is spring loadedtowards the Iocking position.

7. The wire Iocking mechanism (200, 300, 400, 500, 600, 700) according toany previous claim, comprising a first actuator arranged to rotate the excentrearm (240, 340) about the excentre arm center of rotation (255, 355) in a firstdirection to separate the holding member (210, 310) from the counter-holdingmember (220, 320) when in a wire-infeed mode.

8. The wire Iocking mechanism (200, 300, 400, 500, 600, 700) according toany previous claim, comprising a second actuator arranged to rotate theexcentre arm (240, 340) about the excentre arm center of rotation (255, 355)in a second direction opposite to the first direction to move the holding member (210, 310) into the Iocking position.

9. The wire Iocking mechanism (200, 300, 400, 500, 600, 700) according toc|aim 7 or 8, wherein the first actuator and/or the second actuator comprises asolenoid device.

10. The wire Iocking mechanism (500, 600) according to any previous claim,wherein the excentre arm (240, 340) and the counter-holding member (220,320) are supported on a joining member (510, 610), wherein the joiningmember (510, 610) is rotatably supported on a fourth shaft (520, 620) to rotatein relation to a Iocking mechanism body (530) in response to a pull force (F2)acting on the wire (230).

11. The wire Iocking mechanism (300, 400, 600, 700) according to c|aim 2,comprising a control arm arrangement (360), the control arm arrangement(360) comprising an engagement surface (410) for engaging a cylinder cam(420), whereby, upon rotation of the Iocking mechanism body (530) to a pre-determined angle, the control arm arrangement (360) is configured to releasethe catch arrangement (312), thereby placing the first toothed wheel (310) in afree rolling condition and releasing the wire (230) from the wire Iocking mechanism. 21

12. The wire locking mechanism (300, 400, 600, 700) according to claim 11,wherein the engagement surface (410) for engaging the cylinder cam (420)comprises a cylindrical roller configured to traverse the cylinder cam (420).

13. The wire locking mechanism (300, 400, 600, 700) according to claim 5,comprising a catch arrangement configured to lock the second toothed wheelwhen in the locking position.

14. A wire tying device (100) comprising the wire locking mechanism (200,300, 400, 500, 600, 700) according to any previous claim.

15. A control unit (800) configured to control a wire locking mechanism (200,300, 400, 500, 600, 700) for a reinforcement bar, rebar, wire tying device (100),the control unit being configured to; transition (S1) the wire locking mechanism from a neutral position (P1) into a wire infeed mode position (P2); control (S2) wire feed by the wire tying device (100) to receive a wire (230) inthe wire locking mechanism (200, 300, 400, 500, 600, 700); transition (S3) the wire locking mechanism from the wire infeed mode (P2) into a locking position (P3); rotate (S4) a locking mechanism body (530) to tie a knot on the wire (230) and,at a pre-determined angle of rotation; releasing (S5) the wire from the wire locking mechanism (200, 300, 400, 500,600, 700);

16. A wire locking mechanism (200, 300, 400, 500, 600, 700) for areinforcement bar, rebar, wire tying device (100), the locking mechanismcomprising a holding member (210, 310) and a counter-holding member (220,320) arranged to engage respective sides of a wire (230) to releasably holdthe wire in a locking position, wherein the holding member (210, 310) and thecounter-holding member (220, 320) are supported on a joining member (510,610), wherein thejoining member (510, 610) is rotatably supported on a fourthshaft (520, 620) to rotate in relation to a locking mechanism body (530) inresponse to a pull force (F2) acting on the wire (230). 22

17. A wire Iocking mechanism (200, 300, 400, 500, 600, 700) for areinforcement bar, rebar, wire tying device (100), the Iocking mechanismcomprising a holding member (210, 310) and a counter-holding member (220,320) arranged to engage respective sides of a wire (230) to releasably holdthe wire in a Iocking position, wherein the holding member (310) comprises afirst toothed wheel supported on a second shaft (313), and a catcharrangement (312) configured to lock the first toothed wheel when in theIocking position, the Iocking mechanism further comprising a control armarrangement (360), the control arm arrangement (360) comprising anengagement surface (410) for engaging a cylinder cam (420), whereby, uponrotation of the Iocking mechanism body (530) to a pre-determined angle, thecontrol arm arrangement (360) is configured to release the catch arrangement(312), thereby placing the first toothed wheel (310) in a free rolling conditionand releasing the wire (230) from the wire Iocking mechanism.