AU2013101432A4 - A Portable Bending Tool - Google Patents

Description

1 A PORTABLE BENDING TOOL FIELD OF THE INVENTION 5 This invention relates in general to a hand operated device for bending metal bars. The metals bars are typically used in the field of construction equipment, such as bars used to reinforce concrete, generally known as reinforcement bar or rebars, though it may be used for any other appropriate type rod, pipe, tube or malleable material bending. 10 The invention more particularly relates to a portable device that easily bends rebar of different sizes and can be used on the ground at construction sites while using less human effort than conventional techniques and providing maximum safety for the user. 15 BACKGROUND OF THE INVENTION It should be noted that reference to the prior art herein is not to be taken as an acknowledgement that such prior art constitutes common general 20 knowledge in the art. In construction, reinforcing steel is supplied in a variety of different forms. Typically, the reinforcing steel is known as rebar and is available in a variety of diameters and textures. Rebar is placed into concrete form work to increase 25 the tensile strength of the completed reinforced concrete structure. In many types of construction it is often necessary to leave the rebar ends straight where they extend from the concrete structure. In those cases, the extending ends will need to be left straight until after pouring since the level of the concrete may vary depending on the accuracy of the pour. The shape and 30 amount of the rebar which extends after the concrete is poured is important to the structural integrity of the concrete structure which will be poured later. Rebar is commonly provided in fixed lengths, which are shaped and sized to accommodate the structure being formed. The shaping and sizing is done at 2 the construction site as the form takes shape. Consequently, it is desirable to be able to easily shape and size a rebar to a variety of different configurations, within the practical limitations of a construction environment. 5 Further, the structural integrity of the exposed rebar itself is critical to the concrete structure which is poured around the extending rebar. Where the rebar is bent without aid, a sharp bend is made at the surface of the concrete. This is especially harmful and can virtually eliminate the usefulness of the exposed rebar. Early bending devices consist of metal pegs on a wood base 10 used to bend the rebars around the pegs or inserting the rebar into two pipe sections and bending the pipes at the joint between the pipes. As illustrated in FIG 1 known prior art rebar bending methods involve the manual bending of the rebar around an object placed adjacent the rebar where 15 it extends from the concrete. In some cases, the object will move causing most of the bending to be of small radius at the concrete surface. Further, the size of the rebar can cause a different result for different objects over which the rebar is bent. A pipe placed over the rebar is sometimes utilised with the object placed adjacent the rebar where it extends from the concrete to bend the rebar. 20 In this case one construction worker is used to effect the bending and another construction worker is used to hold the object in place adjacent the rebar where it extends from the concrete. The first construction worker uses mechanical advantage by hand or with the use of the pipe placed over the end of the rebar combined with directly tugging and pulling on the rebar or the pipe. Such 25 haphazard bending is problematic for a number of reasons. Firstly, the use of two workers is very time prohibitive and even with two operators the bend and bend radius may still not be suitable. Even with the use of two workers the bending may "trap" the bending device about which the 30 rebar is bent. If the object around which the rebar is bent results in a trap of the structure can cause the workers to have to bend the bar back to free the structure. Bending the rebar both ways significantly weakens the rebar.

3 The majority of known rebar benders are either large stationary units that are located remotely from the work site or manually operated devices that can cause great fatigue to the user and are relatively slow in application. The large stationary units are typically located in factories that preform the rebar for 5 transport to and use at the work site. These devices are relatively large and difficult to transport to the place where the rebar is to be used. The smaller manually operated units are typically smaller hydraulic units but still require that the rebar be transported between the machine and the work site. Typically they cannot be used at the work site location where the rebar is projecting from the 10 concrete the rebar has to be bent prior to being placed into the concrete foundation or wall. Clearly it would be advantageous if a device or tool for bending rebar could be devised that helped to at least ameliorate some of the shortcomings 15 described above. In particular, it would be beneficial to create a portable bending tool which enabled the quick, safe, easy and sure bending of rebar. The portable device or tool should have a number of characteristics which give it functional advantages on the job site. The bending should be able to be achieved at varying heights above the level of the concrete surface. The 20 bending should always produce an even radius of curvature. The bending should be an autonomous task to eliminate the excess use of and expenditure incurred by the construction company. The device used for bending should be portable and as lightweight as possible to facilitate its use between closely set rebar and also at elevations significantly above ground level. 25 SUMMARY OF THE INVENTION In accordance with a first aspect, the present invention provides a portable tool for bending a metal bar comprising: a longitudinally extending 30 support means with a first end for engaging a work surface and an opposing second end for contact with a user; a metal bar engagement means adapted to receive the metal bar within and comprising a user end and a pivot end on the longitudinal axis of the metal bar engagement means; a pivotal means for 4 connecting the longitudinally extending support means and the metal bar engagement means with rotational freedom; and wherein to bend the metal bar to a desired angle the user rotates the metal bar engagement means around the pivot means while supporting themselves against the longitudinally 5 extending support means. Preferably, the metal bar engagement means may comprise a longitudinally extending hollow tube open at the pivot end and adapted to receive the metal bar within. The metal bar engagement means may be 10 removably attached to the pivotal means. The removably attachment means may comprise male and female complementary attachment means. Preferably, the attachment means may comprise a female internal thread located adjacent the pivot end of the metal bar engagement means and a male external thread located on the pivotal means. The metal bar engagement means may 15 comprise a handle grip located adjacent the user end of the metal bar engagement means to allow a user to easily grip and rotate the metal bar engagement means. Preferably, the longitudinally extending support means may comprise a 20 solid steel bar extending from the first end to the second end. A handle may be attached at the second end and forming a right angle with the longitudinally extending support means. Preferably, the handle may comprise a handle grip which allows the users hand to engage and support the portable tool while rotating the metal bar engagement means. 25 Preferably, the portable tool may further comprise an L-shaped member attached adjacent the first end of the longitudinally extending support means and positioned such that the metal bar to be bent is guided to the inside and at the corner formed by the L-shaped member. The long side of the L-shaped 30 member may be permanently attached to the longitudinally extending support member such that a portion of the long side extends at right angles to and either side of the longitudinally extending support member. One portion of the L-shaped member extending at right angles to the longitudinally extending 5 support member may be used to support the foot of the user bending the metal bar to further support and provide leverage for the bending of the metal bar. Preferably, the portable tool may further comprise pivot plates attached 5 at either side of the longitudinally extending support member and spaced from the first end for engaging the work surface. The pivot plates may comprise at least one pivot member retaining openings extending through the pivot plates and the longitudinally extending support member. Preferably, the pivot plates may comprise three pivot member retaining openings which allow the pivot 10 means to be positioned at three different heights from the first end of the longitudinally extending support member and are used to allow the metal bar to be bent at the different heights. Preferably, the pivot means may comprise a pivot pin rotatably retained 15 in one of the pivot member retaining openings to allow the metal bar engagement means to rotate to bend the metal bar. The pivot pin may pass through the pivot plates and the longitudinally extending support member and is rotatably retained in the pivot member retaining openings by a retaining means. The pivot pin may comprise an aperture located adjacent an end of the pivot pin 20 through which the retaining means is passed to rotatably retain the pivot pin in position. Preferably, the retaining means may be a split pin and is passed through the aperture in the pivot pin. Preferably, the pivot pin may be fixedly attached at right angles to a pivot 25 bar, the pivot bar comprising a hollow tube which allows the metal bar to be inserted through the pivot means and into the hollow tube of the metal bar engagement means. Preferably, the male external thread may be located at one end of the 30 pivot bar and the other end of the pivot bar is open to allow the metal bar to pass through and into the hollow tube of the metal bar engagement means.

6 Preferably, the work surface may be a concrete slab and the metal bar may be a reinforcing bar or rebar extending from the concrete slab. The pivot pin may be rotatably retained in any one of the pivot member retaining openings, such that the rebar is bent at the correct height and bend curvature to 5 suit the height of concrete slab to be constructed. BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be understood more fully from the detailed 10 description given hereinafter and from the accompanying drawings of the preferred embodiment of the present invention, which, however, should not be taken to be limitative to the invention, but are for explanation and understanding only. FIG 1 shows an example of the prior art method of bending reinforcing 15 bar or rebar; FIG 2 shows an isometric view of a portable bending tool in accordance with an embodiment of the present invention; FIG 3 illustrates the portable bending tool of Fig 2 in use on a construction site bending rebar; 20 FIG 4 shows a partial side view of the portable bending tool showing the use of the tool for bending rebar to suit different slab heights; FIG 5 shows a front partial cutaway view of the bending tool of Figure 2; FIG 6 shows a sectioned view of the bending tool taken along lines A-A of FIG 5; and 25 FIG 7 illustrates another embodiment of the bending tool in accordance with the present invention. DETAILED DESCRIPTION OF THE INVENTION 30 The following description, given by way of example only, is described in order to provide a more precise understanding of the subject matter of a preferred embodiment or embodiments.

7 With reference to FIG 1, known prior art rebar bending methods involve the manual bending of the rebar 10 around an object 32 placed adjacent the rebar 10 where it extends from the work surface or concrete 20. In this known method two workers 30, 40 are required to bend the rebar 10 in the direction 5 noted by arrow A. One worker 30 uses his hand and fingers 31 to hold the object 32 about which the rebar 10 will be bent by a second worker 40. The second worker 40 typically grips the rebar 10 and pulls it in the direction of arrow A which bends the rebar 10 at the corner 11 around the object 32. The rebar 10 once bent will be used in the construction of the floor 22 above the 10 ground 21. In this example the concrete 20 is concrete footings 20. FIG 2 shows a first embodiment of a portable tool 50 in accordance with the present invention. The portable tool 50 consists of three main components. A first component which is a metal bar engagement means 60 or bending lever 15 within which the metal bar or rebar 10 is inserted and the bending lever 60 is manipulated by a user 30 who utilises mechanical advantage provided by the length of the bending lever 60 to bend the rebar 10. A second component or longitudinally extending support means 70. The support means 70 comprises a first end 74 for engaging the work surface 20 and a second end 72 upon which 20 the user 30 supports their weight to balance the portable tool 50 to provide for the easy bending of the rebar 10. Finally the third main component consists of the pivot means 63 for rotatably connecting the bending lever 60 and the support means 70. 25 The bending lever 60 consists of a longitudinally extending hollow tube 60 which is designed in order to receive the rebar 10 to be bent within the hollow tube 60. At a first end 64 the hollow tube 60 is open to allow the rebar 10 to be inserted inside the bending lever 60. At the opposite end a handle 61 with a rubber or plastic cover is placed over the end of the bending lever 60 to 30 allow the bending lever 60 to be easily gripped and manipulated. The bending lever 60 has been designed to be removably located onto the end of the pivot means 63. This provides the easy replacement of both the bending lever 60 and the pivot means 63 should either become damaged or worn through 8 repeated use of the portable tool 50. An internal thread is located within end 62 of the bending lever 60 which is adapted to screw onto an external thread 65 on the pivot means 63. Obviously the location of the treads is not limited to only the above locations and may be reversed with the internal thread located on the 5 pivot means 63 and an external thread located on the bending lever end 62. The pivot means 63 consists of hollow tube 63 with an opening 64 through which the rebar 10 is passed into the bending lever 60. Adjacent the end 64, a pivot pin 77 is fixedly attached and extends at a right angle away from 10 the pivot means 63. The pivot pin 77 extends through apertures 79 in pivot plates 75, 78 and through the holes drilled in the support means 70. The pivot pin 77 allows the bending lever 60 to be rotated both backwards and forwards in relation to the support means 70. For example, when a rebar 10 is to be bent as shown in FIG 3, the bending lever 60 can be manipulated to rotate in the 15 direction indicated by arrow B. Likewise if the rebar 10 is to be bent in the opposite direction to arrow B the bending lever 60 can be manipulated to rotate in the opposite direction. In order to releasably retain the pivot pin 77 in place a spilt pin 76 is inserted through an aperture located adjacent the end of the pivot pin 77. With the pivot pin 77 retained in place through the pivot plates 75, 78 20 and the holes drilled in the support means 70 the bending lever 60 is able to rotate in an arc backwards and forwards in relation to the support means 70. The split pin 76, also known as a cotter pin or cotter key 76 is a metal fastener with two tines that are bent during installation to retain the pivot pin 77 25 in place. The split pin 76 is typically made of thick wire with a half-circular cross section. The pivot plates 75, 78 are fixedly attached to either side of the support means 70 either by welding the plates to the support means 70 or any other like fixing method. The pivot plates 75, 78 have three openings 79 which pass through both plates 75, 78 and holes drilled in the support means 70. The 30 openings in the plates 75, 78 and the holes drilled in the support means 70 allow the pivot pin 77 to be retained within. The support means 70 consists of a longitudinally extending solid steel 9 bar or tube 70 with a work surface engaging end 74 and a user support end 72. The support means has a handle on the support end 72 which has a rubber or plastic cover placed over the end 72 of the support means or member 70 to allow the user 30 to easily support and balance themselves during the process 5 of bending the rebar 10. The handle and grip 71 are fixedly attached at one end to the end 72 of the support member 70. Fixedly located adjacent the other end 74 of the support member 70 is an L-shaped member 73. The L-shaped member 73 is a sold steel tube with the typical short and long sections forming the L-shape. has two purposes. The L-shaped member 73 is welded to the 10 support member 70 at a point on the L-shaped long section which is approximately at the middle of the long section so that the L-shaped member 73 has a portion of the long section located to one side of the support member 70 and a portion with the short section of the L-shaped member located substantially in line with an axis extending from the end of the bending lever 60. 15 When in this arrangement the rebar 10 is inserted and guided into the portable tool 50 such that the rebar 10 is located substantially within or beside the junction of where the short and long sections of the L-shaped member 73 join. Basically the junction of the L-shaped portions is used to guide and locate the rebar 10 into the bending lever 60. 20 In use and as shown in FIG 3 the portable tool 50 has been designed to allow one worker 30 to perform the job of what has previously been performed by at least two workers. The rebar 10 which protrudes from within the concrete footings 20 needs to be bent at a pre-determined height which is dependent 25 upon the height of the slab or floor to be poured. The portable tool 50 is set up prior to use by placing the pivot pin 77 into one of the openings 79 in the pivot plates 75, 78 and the support means 70. Each opening 79 is at a different height A, B, C as shown in FIG 4. Therefore each opening 79 sets a different height for the slab or floor to be poured. With the pivot pin 77 located in the 30 correct opening 79 for the desired height of the floor the portable tool 50 is now ready for use. The portable tool 50 is lifted and guided over the rebar 10 so that the 10 exposed end of the rebar 10 is placed inside the hollow bending lever 60. By sitting the rebar 10 on the junction of the L-shaped member 73 allows the user 30 to guide the end of the rebar 10 into the end 64 of the bending lever 60. The portable tool 50 is then placed with the surface engaging end 74 of the support 5 means 70 in communication with the work surface 20. This will automatically set the correct height for the rebar 10 to be bent. With the rebar 10 to be bent housed inside the bending lever 60 the portable tool 50 is now ready for use. The user 30 with one hand 31 placed on the handle 71 of the support means 70 and the other hand 33 placed on the handle 61 of the bending lever 60, the 10 user 30 pulls the bending lever 60 in the direction of arrow B until the rebar 10 is bent to the correct angle of curvature for the pre-determined height of the slab. In order to provide more support the user 30 may also place a foot on the L-shaped member 73 to further support the user's weight while bending the rebar 10. 15 With the rebar 10 now bent to the correct angle of curvature and position for the slab the portable tool 50 is slid back towards the user 30 and removed from the rebar 10. The user 30 then simple moves on to the next rebar 10 to be bent. 20 FIG 4 shows the three different heights A, B and C which the rebar 10 can be bent using the portable tool 50. By removing the split pin 76 allows the pivot pin 77 to be removed from the opening 79. Likewise the pivot pin 77 can then be placed in any one of the three openings 79 dependent upon the height 25 A, B, C for the required bent rebar 10A, 1OB or 10C. The portable tool 50 like FIG 3 the bending lever 60 is manipulated in the direction of arrow C in order to bend the rebar 10A, 1OB, 10C to the correct position. FIG 4 also illustrates the positioning of the rebar 10 inside the L-shaped member 73 and inside the bending lever 60. With the portable tool 50 placed over the rebar 10 protruding 30 through the concrete footings 20 and with the end 74 in contact with the footings 20 the bending lever 60 is rotated in the direction of arrow C in order to correctly bend the rebar 10A, 10B, 10C to one of three positions or heights A, B, C dependent upon which opening 79 the pivot pin 77 is placed.

11 FIG 5 illustrates a front view with the portable tool 50 and the pivot pin 77 in the top opening 79. The three different heights for the slab to be poured with the rebar 10 used for reinforcing the slab are shown as X, X+Y and X+Y+Z. As shown with the pivot pin 77 positioned in the top opening 79, the portable tool is 5 set to bend the rebar 10 into position for a slab of height X+Y+Z. Also in FIG 5 a partial section of the support member 70 is shown with the pivot pin 77 retained in the top opening 79 by split pin 76 passing through an aperture in the end of the pivot pin 77. The longitudinally extending solid steel bar support means 70 is also shown with the pivot plates 75, 78 with the three holes drilled 10 to form the openings 79 in the support means 70. In FIG 5 we also show the pivot pin 77 is fixedly attached in this case welded to the hollow tube 63 of the pivot means. On one end of the hollow tube 63 a male external thread 65 screws into the replaceable bending lever 60 with a complimentary internal female thread 62. This also facilitates the easy removal of the pivot pin 77 15 should it become damaged during the process of bending a rebar 10. FIG 6 shows a sectional view of the portable tool of FIG 5 taken along line A-A. Illustrated here we clearly see the pivot plates 75, 78 fixedly attached to the support means 70. In this embodiment the plates 75, 78 are welded to 20 the sides of the support means 70 however it should be understood that any fixing means which provides the attachment of the plates 75, 78 to the support means 70 could be used. Also shown in dotted outline is the pivot pin 77 which passes through both the plated 75, 78 and the support means 70 and is releasably held in place by a split pin 76 passed through an aperture in the end 25 of the pivot pin 77. The pivot pin 77 is securely held in the opening 79 however there is sufficient room to allow the bending lever 60 and the pivot pin 77 to rotate backwards and forwards in relation to the support means 70 in order to bend the rebar 10. 30 Finally FIG 7 illustrates a further embodiment of the present invention showing a portable tool 90. There are only a few minor differences between this embodiment and the previous embodiment and we will only describe those differences. All like components have been numbered the same in both 12 embodiments. This embodiment is basically an economy model 90 of the present invention. In this embodiment the pivot pin 77 is fixedly retained on the bending lever 60 and there is no replaceable bending lever 60 handle and no handle covers. The bending lever 60 is a longitudinally extending hollow tube 5 with an open end 64 for receiving the rebar 10 to be bent. The solid steel longitudinally extending support means 70 has the pivot pin 77 passing through the pivot plates 75, 78 and the drilled holes forming the openings 79. The pivot pin 77 is rotatably retained within the openings 79 by a split pin 76 passing through an aperture in the end of the pivot pin 77. 10 As shown in both embodiments 50, 90 the length of the bending lever 60 is longer than the support means 70. This as is evident provides the mechanical lever advantage required to bend the rebar 10. As with both embodiments 50, 90 the length of the bending lever 60 can be varied to suit the 15 particular job required by simply replacing the removable bending lever 60 with a different length bending lever 60. With the first embodiment 50 the bending lever 60 is unscrewed from the hollow pivot member 63 and replaced. Whereas in the second embodiment the bending lever 60 combined with the pivot pin 77 as one component is replaceable. 20 As previously mentioned the portable tools 50, 90 are manufactured from steel. However some components may be constructed from tough plastics or other suitable materials. For example, the pivot pin may be manufactured from a tough plastic such as Teflon. Likewise to facilitate the rotation of the pivot pin 25 77 and the bending lever 60, bearings (not shown) may be utilised within the openings 79 on either side of the support means 70 and located within the pivot plates 75, 78. ADVANTAGES 30 A well-placed bend of proper curvature is so important to enable the resulting structure to maximally take advantage of the full strength available in the rebar, as well as the holding force of the rebar, which extends parallel to 13 and along the surface of the concrete from which it extends. One result of the need for proper placement of the portable tool is the need to have an even radius bend occur at different selected heights above the surface of the concrete to suit different height floors. Where an object is used to assist the 5 bending of the rebar, it will usually not have the stability to enable the bend to occur at different selected heights. Where the person bending the rebar is using force about an object, the object must be of the correct radius and have an adequate height. The present invention overcomes these problems by providing a portable tool with the ability to be varied to provide for different 10 heights of floor. The present invention reduces the amount of time and effort required to correctly bend the rebar and also only requires the use of one worker to complete the bending process. Furthermore the portable tool is safer than 15 having to have two workers with one worker holding onto a bending object which is placed at the point of bending. Also being portable the tool can be transported to the work site and easily used with rebar that is protruding from the concrete and in close proximity to another rebar. The present invention is portable, compact and lightweight and easily manipulated by a single worker. 20 VARIATIONS It will be realized that the foregoing has been given by way of illustrative example only and that all other modifications and variations as would be 25 apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of the invention as herein set forth. In this specification, adjectives such as first and second, left and right, top and bottom, and the like may be used solely to distinguish one element or 30 action from another element or action without necessarily requiring or implying any actual such relationship or order. Where the context permits, reference to an integer or a component or step (or the like) is not to be interpreted as being limited to only one of that integer, component, or step, but rather could be one 14 or more of that integer, component, or step etc. In the specification the term "comprising" shall be understood to have a broad meaning similar to the term "including" and will be understood to imply 5 the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps. This definition also applies to variations on the term "comprising" such as "comprise" and "comprises". 10

Claims (5)

1. A portable tool for bending a metal bar comprising: a longitudinally extending support means with a first end for engaging a 5 work surface and an opposing second end for contact with a user; a metal bar engagement means adapted to receive the metal bar within and comprising a user end and a pivot end on the longitudinal axis of the metal bar engagement means; a pivotal means for connecting the longitudinally extending support 10 means and the metal bar engagement means with rotational freedom; and wherein to bend the metal bar to a desired angle the user rotates the metal bar engagement means around the pivot means while supporting themselves against the longitudinally extending support means. 15

2. The portable tool as claimed in claim 1, wherein the metal bar engagement means comprises a longitudinally extending hollow tube open at the pivot end and adapted to receive the metal bar within, and the longitudinally extending support means comprises a solid steel bar extending from the first end to the second end. 20

3. The portable tool as claimed in claim 1 or claim 2, further comprising pivot plates attached at either side of the longitudinally extending support member and spaced from the first end for engaging the work surface, the pivot plates comprise at least one pivot member retaining openings extending 25 through the pivot plates and the longitudinally extending support member.

4. The portable tool as claimed in claim 3, wherein the pivot plates comprise three pivot member retaining openings which allow the pivot means to be positioned at three different heights from the first end of the longitudinally 30 extending support member and are used to allow the metal bar to be bent at the different heights.

5. The portable tool as claimed in any one of the previous claims, wherein 16 the pivot means comprises a pivot pin rotatably retained in one of the pivot member retaining openings to allow the metal bar engagement means to rotate to bend the metal bar, and wherein the pivot pin is fixedly attached at right angles to a pivot bar, the pivot bar comprising a hollow tube which allows the 5 metal bar to be inserted through the pivot means and into the hollow tube of the metal bar engagement means.