CONCRETE REINFORCING TYING TOOL

Abstract: A wire tying tool which includes a pair of hollow jaws (12) at one end of a body (11) and a handle (10) telescopically insertable into the other end of the body. The hollow jaws (12) are controlled from the handle (10) so that they can be opened and placed around crossed reinforcing rods (30). Once around the rods (30) the jaws (12) are completely closed with the hollow portions forming a wire guide path substantially encircling the crossed rods (30). Compression of the handle (10) moves a section of ductile wire through the hollow guide. The device is then partially withdrawn from the crossed rods (30) allowing the jaws (12) to open sufficiently to pass by the crossed rods and therefore wrap the ductile wire substantially around the crossed portion of the rods. When the opening of the jaws (12) reaches the top portion of the crossed rods (30) the jaws are then again forced substantially fully closed. The handle (10) is withdrawn from the body (11) which causes the jaws (12) to rotate about the longitudinal axis of the body/handle thereby twisting the wire so as to tighten it about the crossed rods (30).

Description: CONCRETE REINFORCING TYING TOOL The present invention relates to a tool for tying concrete reinforcing rods and/or mesh with ductile wire. In laying form work for steel reinforced concrete it is often necessary to tie together steel reinforcing rod or mesh. This is commonly done by surrounding the intersection of two rods with a piece of ductile wire which is twisted up tightly. BACKGROUND ART The twisting action is often done using a pair of pliers. The prior art includes special tools for guiding wire around the joint and twisting it tightly. The prior art tools have however been heavy, cumbersome and in some cases inefficient in the use of the tie wire. It is therefore an objection of the present invention to ameliorate disadvantages of the prior art. DISCLOSURE OF INVENTION Accordingly, in one broad form, the present invention may be said to consist in a concrete reinforcing tying tool comprising: a body having a main axis; hollow curved jaws pivotally attached to said body and closable around crossed concrete reinforcing rods so as to define a continuous part circular guide path adapted to constrain ductile wire forced there around to follow said guide path; handle means attached to said body and including control means controlling forced closure of said jaws; feed means controlling forced feeding of ductile wire around said guide path; and rotary means controllably rotating said jaws about said main axis. Preferably the body is elongate extending in the direction of the main axis and includes a spiralled drive mechanism and telescopic arrangement so that the handles may be pressed to telescopically shorten the main body, and on pulling the handles on the return stroke the spiralled drive causes the jaws to rotate about the main axis relative to the handles. In another form a pneumatic or electric powered unit forms the rotary means for rotating the jaws about the main axis relative to the handles. The feed means can also be pneumatic or electric powered or alternatively can be incorporated in the telescopically moving handle so that compression of the body causes the forced feeding of the wire around the guide path. The ductile wire may be fed either from a cartridge of precut wires or feed from a continuous spool or similarly wound wire. Where the ductile wire is fed from a continuous spool the device includes a cutting mechanism which cuts the desired length of wire after it has been passed around the hollow curved jaws. This is conveniently done at the end of the downward stroke of the handles. BRIEF DESCRIPTION OF THE DRAWINGS By way of example only, the present invention will now be;- escribed with reference to the accompanying drawing in which: Fig. 1 is an overall view of an embodiment of the invention; Fig. 2 is a detailed view of one component of the device of Fig. 1; Fig. 3 is schematic view of another portion of the device of Fig. 1; Fig. 4 is a further schematic view of a separate portion of the device of Fig. 1; Fig. 5 shows the device in use; Fig. 6 shows a further embodiment of the device; and Figs 7 to 10 show a preferred feature of the invention in various stages throughout the operation of the device. BEST MODE OF CARRYING OUT THE INVENTION The main components of the device shown in Fig. 1 are the handle means 10 connected to a body portion 11, two hollow curved jaws 12 pivotally attached to an end of the body portion 11 opposite to the handles 10, and a wire feeding apparatus 13 located at a convenient position on the body portion 11. In its simplest operation the jaws 12 are opened, either by positive control or by spring means, sothat the joining ends 14 part sufficiently to enable the jaws 12 to be passed around crossed reinforcing rods which are to be tied together. The jaws 12 are then forcibly closed by a control means such as lever 15. The wire feed 13 is then activated forcing ductile wire to pass in to the guide 16 formed in the closed hollow jaws 12. When sufficient ductile wire has been £ passed along the guide 16 and is thus surrounding the two reinforcing rods, the end of the ductile wire closest the wire feed 13 is cut proximate the jaws 12. By maintaining the jaws 12 pressured towards the closed position, while allowing the join 14 to open sufficiently for the device to 10 be pulled upwardly, the ductile wire is caused to bend tightly to conform to the shape of the crossed reinforcing rods until the opening 14 between the jaws 12 is again closed and is above the crossed reinforcing rods with the ductile wire wrapped there around with two free ends held between the 1.5- jaws 12 at the join 14 as shown in Fig. 5. While the handles 10 are prevented from rotation the jaws 12 are caused to rotate thus twisting the ductile wire tightly and securely around the crossed reinforcing rods. The general operation of the device as described above 20 can be realised in a number of manners. Depicted in the drawings is a purely mechanical system in which the body 11 is divided into an upper plunger 17 rigidly attached to the handles 10 and a lower cylinder 18 rigidly attached to the wire feed 13 and having the plunger 17 telescopically 25 inserted therein. A lower portion of the plunger 17 includes spiralled and longitudinal tracks 19 which cooperate with the cylinder 18 so that the plunger 17 may be telescopically forced inwardly of the cylinder 18, causing no relative rotation, then forcibly withdrawn from the cylinder 18 30 causing relative rotation between the two components of the body 11. In this manner there is a two stage action in which rotation of the jaws 12 relative to the handles 10 is performed during the second stage. Depicted in Fig. 3 is a mechanism which cuts the 35 ductile wire close to where it is- introduced to the guide 16. The cutting action is performed at the end of the forced insertion of the plunger 17 into the cylinder 18. The cutting action is performed by a slidable knife 19 biased by a spring 20 and forced in the cutting direction by a captured ball 21. The ball 21 is actuated by an inclined surface 22 located at the bottom of the plunger 17. The knife 19 cooperates with a blade 23 positioned opposite blade 19 along 5 ' a track followed by the ductile wire. Alternatively the cutting action and rotating action could.be provided by pneumatic or electric means. The adaption- of these to the described device is well within the capabilities of people skilled in the art. 10. In the described embodiment the downward movement of the plunger 17 relative to the cylinder 18 can be used to drivet the wire feed 13. The drive mechanism could be a one waygripping device fixed to an appropriate portion of the plunger 1 ' 7 : and gripping a straight section of the wire. 15 Alternatively a rotary wire feed could be used and driven via a one-way ratched mechanism during the forced insertion of the-plunger 17 in to the cylinder 18. Alternative mechanical means:, and the adaption of pneumatic or electric means, is also: well within the capabilities of those skilled in the art. 20 _ Fig. 6 shows an alternative embodiment of the invention wherein the ductile wire is feed from a rotary cartridge 24 which stores a plurality of precut ductile wire sections 25. A feed device such as plunger 26 is synchronised with the movement of handle 10 so as to feed a precut wire section 25 25, into, the jaws 12 in a manner similar to that described in the previous embodiment. Alternative feeding devices such as gravity feed of wire sections 25 into a suitable rotary wire feed could also be used. At a convenient point between the insertion of the wire section 25 into the jaws 12 and the 30 next actuation of the device, the cartridge 24 is caused to rotate so as to allign the next wire section 25 with the entry point to the jaws 12. In Figs. 7 to 10 there is shown in various stages of operation, an additional feature which is advantageously used 5; in conjunction with the jaws 12. A pair of latching arms 27 are pivotally attached to their respective halves of the jaws 12 near the opening 14. In this manner the pivot points of the- arms 27 are brought proximate and distal to one another upon closing and opening of the jaws 12. Each arm 27 includes a latching finger 28 which, in the position as shown in Fig. 9 extends into the hollow position 16 of its respective jaw 12 in a manner which will frictionally engage any wire section 25 position within the jaws 12. The arms 27 have overlapping portions within the area enclosed by the jaws 12. When the jaws 12 are fully open these overlapping portions are free from one another however upon closing of the jaws 12 the arms 27 move toward one another and the overlapping portions contact each other. Further closing of jaws 12 cause the arms 27 to interact and rotate out of the latching position, ie. the overlapping portions move towards the body. The arms 27 extend accross the opening 14 as is clearly seen Fig. 7. Thus when the device is first being inserted over the crossed reinforcing rods 30 the latching arms 27 will be pivoted against the action of their bias springs 29 to an open position as shown in Fig. 8. In this open position a wire section 25 can be inserted as previously described. As the jaws 12 are opened and the device withdrawn from the reinforcing rods 30, as seen " in Fig. 9, the latching arms 2-7 are pulled into the arresting position by the bias springs 29. In the arresting position the fingers 28 frictionally grasp the wire 25 thus tensioning the wire as the device is further withdrawn from the reinforcing rods 30. When the device is sufficiently withdrawn from the reinforcing rods 30 the jaws 12 are again closed and, by interaction of the overlaping portions of the arms 27, the arms 27 are again moved out of the arresting position (Fig. 10). At this point the handle 10 and upper plunger 17 is withdrawn from the lower cylinder 18. In this embodiment, and adoptable generally to other embodiments, the rotating device of the cylinder 18 is rigidly attached to a boss 29 which is rotatably held at the lower end of a main body. The jaws 12 are attached to the boss 29 for rotation therewith upon withdrawal of the upper plunger 17.

Claims: CLAIMS 1. A reinforcing rod tying tool comprising: a body having a main axis; hollow curved jaws pivotally attached to said body and closable around crossed reinforcing rods so as to define, when closed, a continuous part circular guide path adapted to constrain ductile wire forced there around to follow said guide path; handle means attached -co said body and including control means controlling forced closure of said jaws; feed means controlling forced feeding of the ductile wire around said guide path; and rotary means controllably rotating said jaws about said main axis. 2. A tool as defined in claim 1 wherein the body is elongate extending the direction of the main axis and further includes a spiralled drive mechanism and telescopic arrangement cooperative with then handle so that the handle can be pressed telescopically into the main body and withdrawn therefrom, the telescopic arrangement and spiralled drive mechanism rotating said jaws about the main axis relative to the handle upon the withdrawal or insertion of the- handle from or into the main body. 3. A tool as defined in claim 2 wherein insertion of the handles into the main body actuates the feed means and withdraw actuates the spiralled drive mechanism. 4. A tool as defined in claim 3 further including a wire cutting device proximate one of the pair of jaws and intermediate the path around which the wire is fed, the cutting device being actuated at the end of the insertion of the handles. 5. A tool as defined in claim 3 further comprising a cartridge adapted to accept a plurality of precut wire sections, the cartridge being rotated, so as to bring into alingment with the guide path a next wire section, upon each full insertion and withdrawal of the handles. 6. A tool as defined in claim 3 wherein the body includes a boss rotatably attached to an axial end of the boy opposite the handles, the boss being fixed to the spiralled drive mechanism for rotation thereby and wherein the jaws are pivotally attached to the boss. 7. A tool as defined in claim 6 wherein the boss includes a through hole alinged with the guide path proximate and pivotal end of one of the jaws, the through hole further being alinged with the feed means during said forced feeding of the ductile wire. 8. A tool as defined in claim 3 further including a pair of latching arms each pivotally attached to a respective jaw so that opening and closing of the jaws moves the arms distal and proximate one another, each arm includes a finger, which finger extends into the hollow portion of the respective jaw, so as to frictionally engage any wire therein, when the jaws are in the arresting position; a bias means rotationally uring the respective jaw into the arresting position; and an overlapping portion whcih, when the jaws are proximate one another, interacts with the overlapping portion ofthe other jaw so as to move both arms out of their arresting positions.

Inventors: STAVDAL ODD AAGE, STAVDAL, ODD, AAGE
Applicants: STAVDAL ODD AAGE, STAVDAL, ODD, AAGE
Application year: 1986
Main classification: B21F7
IPC codes: E04G21