Abstract:
An application for a device that bends a workpiece includes a rotary hydraulic actuator. The rotary hydraulic actuator is fluidly coupled to a controlled source of hydraulic fluid pressure and has an rotating flange that turns responsive to the hydraulic fluid pressure. A bending member is coupled to the rotating flange of the rotary hydraulic actuator and rotates responsive to the rotational motion of the rotating flange. A bending mandrel is mounted on a face of the bending member at a center of rotation of the bending member and a force mandrel mounted on the face of the bending member. An actuator controls the hydraulic fluid pressure and clips are provided for attaching the device for bending to a boom of, for example, a skid-steer loader.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of U.S. patent application Ser. No. 12/157,433, filed Jun. 10, 2008, the disclosure of which is hereby incorporated by reference. 
    
    
     FIELD 
     This invention generally relates to the bending and forming of metal rods and bars, especially concrete reinforcement bars (rebar). 
     BACKGROUND 
     Concrete reinforcement bar, hereafter referred to as rebar, has been used in construction for many years. Rebar is produced in straight pieces of varying lengths, sometimes up to 40 feet. Rebar needs to be bent before being placed for various reasons such as foundation corners, column “cages” and the like. Until recently, job site bending and cutting was done with a manual tool or machine such as the one invented by Tolman, U.S. Pat. No. 6,418,773 BI. Currently there are several attempts at providing a means to bend and cut rebar on the job site, these include table mounted electrically powered machines, trailer mounted hydraulic and electrically powered machines, small handheld machines, and one known loader mounted hydraulically powered machine invented by Brown, U.S. Pat. No. 5,878,615. 
     Because of the extreme weight and awkwardness of rebar and the normally rough job site terrain, table top machines are not stable enough to efficiently perform. Handheld machines are not designed for larger size rebar or production bending and cutting. Both table top and handheld machines require electrical power, a external hydraulic power source, or both. Trailer towed machines lack the ability to access areas that skid steer loaders do either for job site space constraints or terrain features. 
     Because of their great power, all-terrain ability and the versatility of quickly adding and changing a variety of attachments, skid-steer loaders have become common in the construction industry. Most skid-steer loaders are manufactured with hydraulic connections at the end of the lift arms enabling attachments that require hydraulic power to be used. This all-terrain hydraulic power source coupled with the stable work platform provided by the loaders heavy weight and low profile make my hydraulic rebar bender cutter attachment for skid-steer loader the preferred tool for jobsite metal bending and cutting. 
     Browns device though capable of being attached to a loader vehicle lacks the ability to bend beyond approximately 90 degrees. This is a major limitation since bends of up to 180 degrees are common in the industry. Additionally, although he claims his invention requires only one hydraulic cylinder to perform, it actually has two separate hydraulic cylinders with an accompanied sequencing valve, complicating the process. Therefore a need remains for a simple, reliable, loader mounted rebar bending and cutting attachment that is capable of production bends of up to 180 degrees without repositioning the rebar. 
     What is needed is a system that bends elongated objects and readily attaches to job site equipment such as a skid-steer loader. 
     SUMMARY 
     In one embodiment, a device for bending a workpiece is disclosed including a rotary hydraulic actuator. The rotary hydraulic actuator is fluidly coupled to a controlled source of hydraulic fluid pressure and has a rotating flange that turns responsive to the hydraulic fluid pressure. A bending member is coupled to the rotating flange of the rotary hydraulic actuator and rotates responsive to the rotational motion of the rotating flange. A bending mandrel is mounted on a front face of the bending member and a force mandrel mounted on the face of the bending member. A device is provided for actuating the hydraulic fluid pressure and a device is provided for attaching the device for bending to a boom of, for example, a skid-steer loader. 
     In another embodiment, a device for bending a workpiece is disclosed including a case and a device for converting hydraulic pressure into a rotational force of a bending member. The rotational force is controlled by an actuator and the device for converting hydraulic pressure into a rotational force is mounted within the case and attached to a rear surface. A bending mandrel is mounted on a shaft, the shaft passing through the bending member at center of rotation of the bending member and passing through the device for converting hydraulic pressure into the rotational force. The shaft is affixed to a back surface of the case, preventing it from rotating. A force mandrel is mounted on the face of the bending member and a bracket for attaching the device for bending the workpiece to a boom of, for example, a skid-steer loader is on the rear surface of the case. Placement of a plastically deformable material of elongated shape between the bending mandrel and the force mandrel and actuation of the means for actuating results in rotation of the bending member and bending of the plastically deformable material of elongated shape. 
     In another embodiment, device for bending a workpiece is disclosed including a case and hydraulic supply hoses. The hydraulic supply hoses are connected to a skid-steer loader through an industry standard quick-connect interface. A rotary hydraulic actuator is mounted within and affixed to the case and has an rotating flange that rotates responsive to hydraulic pressure. A hydraulic control valve receives the hydraulic pressure from the skid-steer loader thought the hydraulic supply hoses and controls flow of the hydraulic pressure to the rotary hydraulic actuator in at least two modes. A bending member is coupled to the rotating flange such that the bending member rotates responsive to rotation of the rotating flange. A shaft is affixed at one end to a rear surface of the case and passes through the rotating flange and passes through the bending member, extending out of the bending member. A bending mandrel is removably mounted on the end of the shaft where the shaft extends out of the bending member and a force mandrel is mounted on a face of the bending member. The case has at least one quick attach flange on an outer surface of the case for attaching the case to a machine such as a boom of the skid-steer loader. The rotating flange and bending member rotate around the shaft when the hydraulic pressure is applied to the rotary hydraulic actuator. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention can be best understood by those having ordinary skill in the art by reference to the following detailed description when considered in conjunction with the accompanying drawings in which: 
         FIG. 1  is an isometric front view with the control switch attached. A piece of rebar is inserted and ready to bend. 
         FIG. 2  is an isometric back view with the case, rear cover, work tray and quick-attach flanges removed for better viewing of the internal parts. 
         FIG. 3  is an exploded view of the internal parts. For clarity the case, rear cover, work tray, quick-attach flanges, electrical and hydraulics are not displayed. 
         FIG. 4  shows the machine with a piece of rebar positioned on the work tray and bent 90 degrees. The control switch is unplugged and not shown. 
         FIG. 5  shows the machine with a piece of rebar positioned on the work tray and bent 180 degrees. The control switch is unplugged and not shown. 
         FIG. 6  shows the machine with a piece of rebar inserted in the cutting-zone and ready to be cut. 
         FIG. 7  shows the machine with a piece of rebar inserted in the cutting-zone and cut. 
         FIG. 8  shows an exploded view of the case and work tray components. 
         FIG. 9  shows a rear isometric view of the work tray for viewing of the adjustment pins. 
         FIG. 10  is an isometric front view of an alternate embodiment with the control switch attached. A piece of rebar is inserted and ready to bend. 
         FIG. 11  is an exploded view of the alternate embodiment showing the relationship of internal parts. 
         FIG. 12  shows a front perspective view of the alternate embodiment with a piece of rebar positioned on the work tray and bent 90 degrees. 
         FIG. 13  shows a front perspective view of the alternate embodiment with a piece of rebar positioned on the work tray and bent 180 degrees. 
         FIG. 14  shows a rear perspective view of the alternate embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to the presently preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Throughout the following detailed description, the same reference numerals refer to the same elements in all figures. 
     The disclosed machine bends and/or cuts elongated bendable objects such as concrete reinforcement bar commonly known as “Rebar”. For the purpose of these specifications the term “Rebar” will be used throughout. This is not to limit the scope to only rebar since the machines design favors bending any kind of plastically deformable material that is elongated in shape. In addition, the preferred embodiment of the machine is to be mounted and hydraulically powered by a “skid-steer” loader vehicle. For the purposes of these specifications the term “skid-steer” will be used throughout. This is not to limit the scope of the machine to skid-steer loaders since by design it is capable of being mounted and powered by any type of vehicle with a hydraulic power source of sufficient output to operate the machine, such as backhoes, tractors, articulating loaders, forklifts and the like. 
     In one embodiment, the bender machine is comprised of a hydraulic cylinder  23  attached to a case  22  on the cylinder end, and to a rack gear slide-bar assembly  26  on the hydraulic ram  25  end. The slide-bar rack gear assembly  26  travels laterally through a slide channel  30 . The purpose of the slide channel  30  is to guide the slide-bar rack gear assembly  26  as it travels back and forth. A pinion gear  28  is free mounted on a fixed axel  12  in such a manner that it engages the slide-bar rack gear assembly  26 . When the hydraulic cylinder  23  is powered the slide-bar rack gear assembly  26  moves laterally causing the pinion gear  28  to turn proportionally. A bending disc  27  is connected to the pinion gear  28  and mounted on the common fixed axel  12  so as to turn in unison with the pinion gear  28 . Although shown as a bending disc  27 , there is no requirement that this component be shaped as a disc. Both the pinion gear  28  and the bending disc  27  rotate freely on the fixed axel  12 . The fixed axel  12  penetrates the front face of the case  22  and acts as a mounting shaft for various size mandrels. The portion of the fixed axle  12  that protrudes outside the front of the case  22  will be identified as the bend shaft  40 . 
     The bending disc  27  has a force shaft  33  mounted toward the outside edge and perpendicular to its face. Said force shaft travels in a circular cut-out  17  in the face of the case  22 . The force shaft  33  is of the same diameter as the bend shaft  40  so as to allow mandrels to be interchanged. The mandrels here forward will be called the force mandrel  16  when installed on the force shaft  33  and the bend mandrel  13  when installed on the bend shaft  40 . The force mandrel  13  and the bend mandrel  16  vary in size to accommodate industry standard minimum bend radii. The fixed axel  12  is fixed in position so as not to rotate when the pinion gear  28  and the bending disc  27  rotate. 
     The force shaft  33  is fixed in position so as not to turn. The force shaft  33  has a shoulder to keep the force mandrel  13  from contacting the face of the case  22  when it is installed. The end of the force shaft  33  is drilled and tapped to accept a retaining bolt  15  and retaining washer  14 . The retaining bolt  15  and retaining washer  14  prevent the force mandrel  16  from coming off the force shaft  33 . The length of the force shaft  33  is such that when the retaining bolt  15  and the retaining washer  14  is installed and tightened the force mandrel  16  can rotate freely. This allows the force mandrel  16  to roll over the rebar  1  and around the bend mandrel  13  as the machine is working. 
     Mounted on the face of the case  22  is an adjustable work tray  19  used to position and support the rebar  1  while bending. The work tray  19  has two adjustment pins  35  mounted on the face that contacts the case  12 . The adjustment pins  35  are positioned towards the ends of the work tray  19 . The case  22  has a series of adjustment holes  34  positioned horizontally so as to line up with the work tray  19  adjustment pins  35 . The adjustment holes  34  are positioned vertically at a height on the case  22  so as to allow the work tray  19  to be positioned the proper increment up or down according to the rebar  11  size. The adjustment holes  34  are also positioned vertically at an angle so as to move the work tray  19  horizontally closer to the bend mandrel  13  when smaller sizes are installed thereby keeping a uniform distance between the bend mandrel  13  and the end of the work table  19 . The work table  19  is secured to the case  22  with an adjustment bolt  20  and an adjustment knob  37 . The adjustment bolt  20  is allowed to travel vertically in an adjustment slot  43  cut in the case  22 . The adjustment slot  43  is cut at the same angle as the adjustment holes  34 . To adjust the height of the work tray  19  simply loosen the adjustment knob  37  to allow the enough space between the case  22  and the work tray  19  to disengage the adjustment pins  35  from the adjustment holes  34 . Position the work tray  19  to the desired level by lining up the adjustment pins  35  with the adjustment holes  34  and tighten the adjustment knob  37 . 
     The bend shaft  40  is drilled and tapped to accept a retaining bolt  15  and retaining washer  14 . The purpose of the retaining bolt  15  and retaining washer  14  are to secure the bend mandrel  13  on the bend shaft  40 . The length of the bend shaft  40  is slightly shorter than the bend mandrels  13  depth. When the bend mandrels  13  retaining bolt  15  and retaining washer  14  is installed and tightened the bend mandrel  13  will be drawn snuggly against the front of the case  22  thereby preventing it from rotating. This keeps the rebar  11  from rolling forward when bending. 
     The hydraulic cylinders  23  fluid and pressure is supplied by the skid-steer loader through hydraulic hoses  32  with industry standard quick-connect fittings. When the hydraulic supply hoses  32  are connected to the skid-steer, hydraulic pressure flows through the hydraulic supply hoses  32  to the hydraulic manifold  24 . An electric solenoid hydraulic control valve  41  mounted in the hydraulic manifold  24  controls the flow of hydraulic fluid from the hydraulic manifold  24  to the hydraulic cylinder  23 . The hydraulic control valve  41  is powered, for example, from the skid-steer loaders electric system by connecting the machines power supply cord  39  to the skid-steer loaders power receptacle mounted on the boom. 
     Actuation of the hydraulic control valve  41  is accomplished by an actuation device such as a foot pedal or a hand selector switch. In an alternate embodiment the hydraulics are controlled by a manual spool valve. In still other embodiments, programmable logic controllers are incorporated for automation. From here forward we will refer to the actuating device as a control switch  36 . 
     To operate the Hydraulic Bender Cutter machine, attach the machine by maneuvering the skid-steer loader so as the loaders mounting plates engage the quick-attach flanges  31  on the back of the machines case  22 . Attach the hydraulic supply hoses  32  to the skid-steers hydraulic quick-connect fittings. Raise and tilt the machine to the desired work height and angle. 
     Install the proper size force mandrel  16  on said force shaft and secure the force mandrel  16  by installing the retaining washer  14  and the retaining bolt  15  in the tapped hole in the force shaft  33 . Install the proper size bend mandrel  13  on the bend shaft  40  and secure the bend mandrel  13  by installing the retaining washer  14  and the retaining bolt  15  in the tapped hole in the bend shaft  40 . 
     Adjust the height of the work tray  19  by loosening the adjustment knob  37  to allow enough space between the case  22  and the work tray  19  to disengage the adjustment pins  35  from the adjustment holes  34 . Position the work tray  19  to the desired level by lining up the adjustment pins  35  with the adjustment holes  34  and tighten the adjustment knob  37 . 
     Place the rebar  11  on the work tray  19  and position the rebar  11  laterally so that the desired bend point is under the bend mandrel  13 . It is anticipated that the bender will bend multiple rebar  11  sections simultaneously by stacking the bars flat on the work tray. When ready to bend, activate the control switch  36  in the bend direction. Release the control switch  36  when the bend has reached the desired angle. Return the force mandrel  16  to the start position by activating the control switch  36  in the return direction. 
     For cutting, with the hydraulic cylinder  23  in the retracted position, place the rebar  11  in the cutting zone  18  and activate the control switch  36  as if bending. When the cutter blades  29  meet, the rebar  11  will be cut. To open the cutter blades  29  for another cut, simply activate the control switch  36  in the return direction until the cutting zone  18  is clear. 
     Referring to  FIGS. 10-14 , in another embodiment, the bending device  101  utilizes a rotary hydraulic actuator  123  instead of the linear actuator  23 . Although a rotary hydraulic actuator  123  is described throughout this specification, any type of rotary actuator or rotary motor that is powered by hydraulic pressure is anticipated, for example, a hydraulic motor, etc. This embodiment includes in a bending device  101  that performs the same or similar bending operation as the first embodiment. The bending device  101  includes a rotary hydraulic actuator  123  attached to a case  122  by, for example, screws  173  and washers  172 . In a preferred embodiment, a front support  144  integral or affixed to the case  122  provides additional support to the front area of the rotary hydraulic actuator  123 . In such, an opening in the front support  144  is sized to tightly fit the rotary hydraulic actuator  123  and support the rotary hydraulic actuator  123 , especially during bending operation. When the rotary hydraulic actuator  123  is powered by hydraulic pressure, the rotating flange  160  rotates. A bending disc  117  is connected to the rotating flange  160  by, for example, screws  161  and the bending disc  117  turns in unison with the rotating flange  160 . Although shown as a bending disc  117 , there is no requirement that this component be shaped as a disc. 
     The bending disc  117  turns in unison with the rotating flange  160 . In a preferred embodiment, a bend shaft  120  passes through the rotating flange  160  to the back surface of the case  122 . In preferred embodiments, the bend shaft  120  extends from the bending disc  117 , through the rotary hydraulic actuator  123  and is bolted to the back surface of the case  122  using, for example, by a washer  142  and nut  143 . This provides for added strength. Although, in some embodiments the bend shaft  120  rotates with the rotating flange  160 , it is preferred that the bend shaft  120  not rotate as will be discussed later. In some embodiments, the bend shaft  120  has a non-round (e.g. square, triangular, etc) end that mates with a similar shape opening in the back surface of the case  122 . This further prevents the bend shaft  120  from turning. Therefore, the bending disk  117  rotates around the bend shaft  120  while the bend shaft  120  remains stationary with the assistance of an optional bearing  145  which is press-fit into the bend disc  117 . 
     The bending disc  117  has a force shaft  133  mounted perpendicular to its face in any of one or more holes  146  spaced at differing distances from the center of the bending disc  117 . In some embodiments, the force shaft  133  is of the same diameter as the bend shaft  120  so as to allow mandrels  113 / 116  to be interchanged. The mandrels  113 / 116  include a force mandrel  116  installed on the force shaft  133  and a bend mandrel  113  installed on the bend shaft  120 . The force mandrel  113  and the bend mandrel  116  vary in size to accommodate industry standard bend radii. In the preferred embodiment, the bend shaft  120  is fixed in position so as not to rotate when the bending disc  117  rotates. In such, when the rebar  111  is bent by a force of the force mandrel  116  orbiting as the bending disc  117  rotates, the rebar  111  isn&#39;t pulled horizontally by rotation of the bend mandrel  113  since the bend mandrel  113  is coupled to the shaft which is fixed to the rear surface of the case  122  and, therefore, does not rotate. 
     In one embodiment, an end of the bend shaft  120  is drilled and tapped to accept a retaining bolt  115  and retaining washer  114 . The retaining bolt  115  and retaining washer  114  hold the bend mandrel  120  on the end of the bend shaft  120 . Any other attachment mechanism is anticipated; including quick connect/disconnect attachment mechanisms. 
     In this example, the force mandrel  116  is mounted to the bending disc  117  on a force shaft  133 . The force shaft  133  is affixed or screwed into one or more holes, threaded holes or slots  146  in the bend disc  117 . It is preferred that for a threaded interface, the threads are reverse-threaded to reduce issues with the force shaft  133  coming lose during bending. It is preferred that the force mandrel  116  rotates freely on the force shaft  133 . This permits the force mandrel  116  to roll over the rebar  111  while the force mandrel  116  orbits the bend mandrel  113  as the machine bends the rebar  111 . Alternatively, the force mandrel  116  is fixed to the force shaft  133  and the force shaft  133  is rotatably interfaced to the bend disc  117 , providing a similar feature. The force mandrel  116  is held to the force shaft  133  in any way known in the industry including a tapped end on the force shaft  133  using a bolt  115  and washer  114  as with the bend shaft  120 . It is also anticipated that the bend mandrel  113 , as with the force mandrel  116 , is mounted to the shafts  120  using quick-release devices for simplified exchange. 
     In a preferred embodiment, an adjustable work tray  119 / 137 / 140  is mounted on the face of the case  122  for positioning and supporting the rebar  111 . The work tray  119 / 137 / 140  has an adjustment pin  137  that pass through an outer bracket  140  and holds a work surface  119  in a proper position such that the rebar  111 , is held parallel to the top surface of the work surface  119  properly contacts the bend mandrel  113 . The work tray  119 / 137 / 140  has a series of adjustment holes positioned horizontally so as to adjust the work surface  119  properly for a variety of different sized bend mandrels  113 . Lack of rotation of the bend mandrel  113  prevents the rebar  111  from moving horizontally while bending is performed. There are many known ways to provide an adjustable work surface  119 , all of which are anticipated and included here within. 
     Fluid pressure is supplied by the skid-steer loader through hydraulic hoses  132  with industry standard quick-connect fittings. When the hydraulic supply hoses  132  are connected to the skid-steer, hydraulic pressure flows through the hydraulic supply hoses  132  to the hydraulic manifold/valve  124 . The hydraulic manifold/valve  124  controls the flow of hydraulic fluid from the hydraulic manifold/valve  124  to the rotary hydraulic actuator  123  through hydraulic tubes  152 . In embodiments where the hydraulic manifold/valve  124  is powered by electric current, a power connection  139  is provided. For example, the power cord  139  connects to the skid-steer loaders electric system through the skid-steer loaders power receptacle. In some embodiments, power is provided to the hydraulic manifold/valve  124  by a battery system (not shown). In some embodiments, the hydraulic manifold/valve  124  is a manually operated valve, requiring no electric power. 
     Actuation of the hydraulic manifold/valve  124  is accomplished by an actuation device such as a foot pedal or a hand control switch  136 . In come embodiments, the switch  136  has a plug end  129  that mates with a jack  130  on the hydraulic manifold/valve  124 . In an alternate embodiment, programmable logic controllers or the like are incorporated for automation. 
     The hydraulic manifold/valve  124  has three operating modes. In a first operating mode, hydraulic fluid flows freely from the skid-steer loader output port, through the hydraulic manifold/valve  124  and back to the skid-steer loader input port so as to not load the hydraulic pump system within the skid-steer loader. In a second operating mode, the hydraulic manifold/valve  124  routes the hydraulic fluid (under pressure) through the hydraulic tubes  152  and through the rotary actuator  123  in a first direction, causing the rotary actuator  123  to turn in a first direction. In a third operating mode, the hydraulic manifold/valve  124  routes the hydraulic fluid (under pressure) through the hydraulic tubes  152  and through the rotary actuator  123  in a second direction, causing the rotary actuator  123  to turn in a an opposite direction. 
     In some embodiments, handles  141  are provided for manual lifting of the bender machine  101 . 
     To operate the bender machine  101 , attach the bender to a skid-steer loader by maneuvering the skid-steer loader so as the loaders mounting plates engage the quick-attach flanges  131  on the back of the machines case  122  as shown in  FIG. 14 . Quick-attach flanges  131  are well known in the industry and often include a top and bottom engagement mechanism  131  as shown in  FIG. 14 . 
     The hydraulic supply hoses  132  are attached to the skid-steers hydraulic quick-connect fittings. Raise and tilt the bender to the desired work height and angle. 
     Install the proper size force mandrel  116  on the force shaft  133  by inserting the shaft  133  into the force mandrel  116  and screwing shaft  133  into one of the threaded holes  146 . Install the proper size bend mandrel  113  on the bend shaft  120  and secure the bend mandrel  113  by installing the retaining washer  114  and the retaining bolt  115  in the tapped hole in the bend shaft  120 . 
     Adjust the height of the work tray  119  to the desired level by lining up the adjustment holes and insert the adjustment pin  137 . 
     Place the rebar  111  on the work tray  119  and position the rebar  111  laterally so that the desired bend point is under the bend mandrel  113 . It is anticipated that the bender will bend multiple rebar  111  sections simultaneously by stacking the bars flat on the work tray. When ready to bend, activate the control switch  136  in the bend direction. Release the control switch  136  when the bend has reached the desired angle. Return the force mandrel  116  to the start position by activating the control switch  136  in the return direction. 
     Equivalent elements can be substituted for the ones set forth above such that they perform in substantially the same manner in substantially the same way for achieving substantially the same result. 
     It is believed that the system and method as described and many of its attendant advantages will be understood by the foregoing description. It is also believed that it will be apparent that various changes may be made in the form, construction and arrangement of the components thereof without departing from the scope and spirit of the invention or without sacrificing all of its material advantages. The form herein before described being merely exemplary and explanatory embodiment thereof. It is the intention of the following claims to encompass and include such changes.