Patent Grant
7743636
This invention relates to a rotary draw tube bender with a rotating spindle and arm driven by a dual hydraulic drive via an electro-hydraulic control system with foot pedal controls, and aligned with a ratchet mechanism to incrementally and accurately set the gap between the bending die and counter-die.
Many buildings, construction sites, manufacturing plants and machine shops require or use a significant quantity of bent tubes, pipes and rods to produce items such as hand rails, scaffolding, or fabricated metal products. A variety of conventional machines have been developed to facilitate the otherwise difficult task of bending of rigid metal tube or pipe into a desired shape. One type of tube bending machine is the rotary draw bender. This bending machine 5 uses a bending die with a concave groove. The groove is uniform in shape and diameter around the circumference of the die. The bending die has a corresponding counter-die, which combine to form a die set. The forward wall of the counter die has a linear channel that forms a concave groove along its length. This straight groove flushly receives the straight tubular workpiece. The diameter of the groove of the bending die is the same as its corresponding counter die, and both die can have a circular or slightly elliptical shape. The diameter of the grooves of a die set match the outside diameter of the tubular workpiece that they will bend.
A rotary draw tube bending machine 5 with a hydraulic drive is shown in
The bending machine 5 uses a mounting assembly 8 to hold the counter-die. The assembly 8 has two downwardly extending bolts that are received by spaced holes 9 drilled into the top of the rotating arm. The posts are inserted into selected holes 9 to fix the assembly 8 in place, and position the counter-die with the bending die. For example, a hole 9 drilled at a location for a bending die made to form a two inch bend radius into a one inch diameter ASTM schedule 40 pipe, would be about one inch away from another hole 9 drilled for a bending die made to form a three inch bend radius into a one inch diameter schedule 40 pipe. The mounting assembly includes a pivot post and swing assembly to swing the counter-die into and out of engagement with the bending die. Swinging the counter-die out of engagement allows a straight workpiece 10 to be loaded, or a bent workpiece 15 to be unloaded. The machine 5 also includes a bend angle setting device with a protractor-like dial and a stop switch. The switch automatically deactivates the hydraulic drive when the machine reaches the desired pre-set bend angle.
An unbent workpiece 10 is loaded into the bending machine 5 by placing it in an outer concave groove of the bending die. The outer wall 12 of the workpiece 10 flushly engages the concave groove of the die. The straight workpiece 10 is tangent to the circular bending die. The bending die has a hook that engages the opposite side of the tubular workpiece to secure it to the bending die. The counter die and mounting assembly 8 are picked up and set onto the rotating arm with its posts mating selected holes 9 to set the die gap for the particular die set. The counter-die is then swung into pressing engagement with the workpiece 10 to fix the workpiece to the bending die via its hook. When the bending die is rotated, the tube 10 is drawn by the hook, pulled through the channel of the counter die, and wrapped around the groove of the bending die.
The combined rotation of the bending die and rotating arm determines the bend angle of the tube 15. The shape of the bend 16 is determined by the radius of the bending die, the shapes of the arcuate grooves of both dies, and the gap between the dies during the bending process. The groove of a typical bending die has a semi circle shape. The groove of the counter-die has an engineered shape that is slightly elliptical and slightly less than a semi-circle. The edges of the counter-die do not directly contact the edges of the bending die when they are brought together to hold and substantially surround the workpiece 10. The edges of the dies are spaced apart to form a die gap of about ⅛ inch.
The die gap must be properly set to attain a desired bend shape that is free from irregularities in the bend region 16. The bend region 16 of the tube or pipe 15 should have a continuous bend, a desired uniform radius, and a rounded outer portion 17. The die gap determines the amount of pressure the counter-die exerts on the tube 10 during the bending operation. If the gripping pressure is too high, the tube 10 will bind with the counter-die, and slide through the hook during the bending process. A properly set die gap prevents slipping. Slipping results in the tube sliding through the hook and bending die groove, disengages from the bending die, and forms a kink in the tube. This kinking creates a non-continuous bend with a non-uniform radius, which is visually and dimensionally unacceptable, so that the tube has to be scrapped.
The die gap ensures that the groove surface of the counter-die remains flushly engaged with the outer surface 12 of the tube or pipe 10 when forming the bend. During the bending process, the rounded outer portion 17 of the workpiece 10 should conform to the shape of the counter-die, even when the groove surface is slightly elliptical as shown in
Conventional tube bending machines should accommodate various dies and die sets, such as those shown in
A problem with conventional tube bending machines is that they only form a limited number of bends. The machines are specifically designed and manufactured for use with a limited number of bending dies and die sets, and thus only accommodate certain diameter tubes or pipes 10, and only form specific bend radii in those tubes and pipes. For example, the spaced linear holes 9 in the rotating arm of the rotary draw tube bending machine 5 shown in
Another problem with conventional tube bending machines is that they do not allow field operators to adjust the die gap, such as to allow for variations in workpiece diameter. Although field operators may try to bend workpieces with a slightly different diameter than the bending machine was made, these slight changes in diameter can have a significantly negative affect on the shape and quality of the bends being formed. The workpiece can slip if the gripping pressure is reduced, or bind, break or increase wear if the workpiece is gripped too tight.
A further problem with conventional tube bending machine is its cost and difficulty to repair. Although some tube bending machines provide a hand wheel and screw assembly for setting the die gap, these machines are much more expensive. The cost of the wheel and screw assembly is significant. The wheel and screw assembly also requires a device such as a numerical counter so that the operator can repeatedly return the counter-die to the same desired position each time for repeating a particular bend on many workpieces. The operator must remember to write down the desired positioning number so that the wheel can be returned to this position each time. If the operator forgets to write down the positioning number, then they will not be able to accurately repeat the bend on a new workpiece. In addition, any damage to or wear and tear on this assembly requires immediate repair. Yet, this assembly is time consuming to remove and replace, and because of its significant cost, replacement parts are difficult to obtain, all of which leads to costly down time.
A still further problem with conventional rotary draw bending machines is operating efficiency and safety. During operation, a worker is constantly handling straight and bent pieces of tubing or piping. Straight tube must be properly placed in the machine by hand, and the bent tube must be removed from the machine by hand. Control switches are also operated by hand. Machine efficiency is reduced because a person can only reliably do one of these tasks at a time. The control switches also require the operator to be close to the machine to start and stop a bend. The worker must get close to the machine to turn it off even if something is noticeably wrong, such as a workpiece is binding, which could suddenly release in a snapping motion and injure the worker.
A still further problem with conventional rotary draw bending machines is their many hydraulic hoses. A variety of hoses are needed to balance the pressure and flow rate of the hydraulic fluid to the drive cylinders so that the drive rods extend symmetrically at the same rate. These hoses are not protected and can be easily crushed, punctured, cut or otherwise damaged in a busy construction site or manufacturing setting. The flex hoses also require many connections that can loosen or leak. Yet, hydraulic fluid leaks are both messy and lead to dangerous and slippery work conditions.
A still further problem with conventional tube bending machines is die change over time. Dies are frequently changed during operation. Yet, the dies on many machines are difficult and time consuming to change. Many conventional tube bending machines typically require special tools or the removal of several parts to change either the bending die or the counter die. Accordingly, a significant down time occurs each time a different radius bend is formed or a different diameter workpiece is loaded. Moreover, should a part that needs to be removed to change a die become jammed, stripped or damaged, the entire machine may become inoperable until it is repaired.
A still further problem with conventional tube bending machines is that they are bulky and difficult to move. A worker performing a project in a specific area of a construction site or manufacturing plant may have to haul large quantities of bulky, heavy tubing or pipe from one end of the site or plant to the other and back in order to perform his or her job. This is not only an unproductive use of work time, but can result in injury to the workers.
The present invention is intended to solve these and other problems.
The present invention relates to a rotary draw bending machine and a process of using that machine to bend workpieces such as tubes or pipes into precise bends. The bending machine has a spindle holding a bending die, and a radial arm holding a counter-die. The spindle and arm are simultaneously rotated in opposite directions by the dual hydraulic drive. Each rotates half the desired bend angle. The desired bend angle is set by a dial with a triggering groove that are rotated relative to a fixed limit switch. The hydraulic drive moves the machine between a home positioned at 0° and the desired bend angle position. The machine is controlled by an electro-hydraulic control system with foot pedal controls. The radial arm has an alignment mechanism formed by a track that slidingly receives the counter-die assembly. A ratchet mechanism incrementally aligns the counter-die with the bending die. Ratchet teeth allow incremental advancement of the counter-die when aligning it with its bending die to accurately set the proper gap between the counter-die and bending die. The ratchet mechanism preferably includes a fine tuning device to provide an infinite range of adjustability for setting the die gap.
An advantage of the present tube bender is its die gap alignment mechanism. The alignment mechanism is located on the rotating arm and includes a slide track and ratchet mechanism. The alignment mechanism provides incremental, adjustable positioning of the counter-die relative to the bending die. The saw-tooth shape of its ratchet teeth and the tip shape of the ratchet arm allow forward sliding movement of the counter-die assembly, and selectively prevent rearward movement. This incremental sliding movement positions the counter-die near the bending die with a relatively small, but necessary, incremental gap between them. A gap of about ⅛ inch between the ends of the dies is common. This gap ensures that the counter-die properly holds and maintains contact with the tubular workpiece during the bending operation. The counter-die snuggly presses the workpiece, but not so tight as to cause undesired binding. An overly tight grip causes the workpiece to bind with the counter-die, which causes the workpiece to slip through the hook of the bending die. Too loose of a grip and the workpiece will disengage from the counter-die in the critical bend forming region, which results in an improperly rounded or flattened bend surface.
Another advantage of the present tube bender is the speed, ease of use and reliability of the gap alignment mechanism. The machine and its ratchet assembly are designed for use with a wide variety of dies and a wide variety of workpiece diameters. Each bending machine includes several sets of dies. Each set is made for a certain workpiece diameter (e.g. 2 inch ASTM schedule 40 pipe). Each die set includes one counter-die and several corresponding bending dies. The bending dies are typically made in standard radial increments, such as 3 inch, 3¼ inch, 3½ inch, 3¾ inch, 4 inch, 4¼ inch, etc. When the tubes or pipes being bent at a job site have the same diameter, or multiple bends are formed into various tubes or pipes, then the same set of dies is used for multiple bends of various radii. In these situations, the same counter-die is used, and the bending dies are changed to change the bend radius. The bending die and counter die are removably secured to their respective mounting brackets to facilitate quick die changes. The alignment mechanism is particularly fast and easy to use in these situations, because the change in the die gap basically corresponds in a one-to-one ratio to the change in the radius of the bending die, and the change in the radial increments of the bending dies is a multiple of the incremental ratchet length. For example, when the die gap is set for a 4¼ inch radius bending die, then switching to a 3½ inch radius bending die requires move the counter-die forward ¾ inch. This sliding movement is easily accommodated by the alignment mechanism because each ratchet tooth has a length sized to provide a desired uniform incremental advancement of the counter-die along the track relative to the bending die. The length of one tooth is an integer fraction of the difference in the radii of two bending dies. For a bending machine that includes bending dies with these radii, the ratchet teeth have a length of ⅜, ¼, ⅛ or 1/16 inch. This allows the counter-die to be easily slid into position with the 1½ inch bending die with the desired ⅛ inch gap by simply sliding the counter-die assembly forward three, six or twelve teeth, respectively. This simple motion is performed quickly when changing bending dies, to accurately align the dies with the desired gap between them. A template can be placed over the ratchet assembly, or the ratchet assembly can be directly marked, to indicate the proper ratchet slot for each bending die in a particular set. Quickly and accurately setting the gap is important because the bending machine is constantly being reset to form a different radius bend or bend a different diameter pipe. The initial setting of the die gap effectively sets the die gap for each of the bends, even when the bend radius changes throughout the day. Thus, the alignment mechanism minimizes worker frustration, increases the speed of setting the gap and reduces scrap, which results in less material waste, improved labor efficiency, and less drain on tubing or piping inventor. Costly time delays to obtain additional inventory are avoided, which is particularly advantageous when the pipe being bent is required to begin or complete other work, such as erecting scaffolding or installing electrical conduit runs.
A further advantage of the present tube bending machine is its inexpensive cost. The alignment mechanism uses component parts that are easily and inexpensively manufactured to produce a machine that accurately sets and adjusts the die gap. The track and ratchet assembly are cost effective and durable. When necessary, the ratchet assembly can be easily removed and replaced, without undue expense or down time.
A still further advantage of the present tube bender is its quick release mechanism. The counter-die can be swung to the side to release or insert a workpiece, and back again into proper aligned engagement with the workpiece. The quick release mechanism does this without moving the counter-die assembly, so that the proper die gap setting is maintained. The quick release improves the operational efficiency of the tube bender because die gap does not need to be reset when the machine is used to make consecutive bends of the same radius to a single piece of pipe or pieces of pipe with the same diameter.
A still further advantage of the present tube bender is that it firmly holds and locks the counter-die assembly in place. Maintaining the proper position of the counter-die is important because the counter-die exerts up to about 4,000 pounds of force on the pipe during operation as the machine draws or pulls the pipe around the bending die. The track and ratchet mechanism allow quick positioning of the counter-die assembly. The assembly also includes two locking bolts that absorb the large bending forces. These bending forces are not seen by the ratchet mechanism to any significant extent, which would increase the wear rate of its teeth and pivot mechanism, and reduce the precision of its incremental alignment function. The pivot post of the quick release mechanism includes one of the locking bolts. When tightened, the bolt compresses the pivot post, which increases its torque resisting strength. The second locking bolt provides extra support to filmy hold and lock the counter-die assembly in place on the slide track of the rotating arm.
A still further advantage of the present tube bender is its fine tuning mechanism for setting the die gap. The fine tuning mechanism includes a circular rotatable hub with an offset shaft to secure the hub and the ratchet mechanism to the rotatable arm. The offset between the center of the hub and the center of its securement shaft is at least substantially equal to half the length of one ratchet tooth. Hub rotation positions the counter-die half a tooth forward or half a tooth backward. Thus, in combination with the incremental alignment and adjustability of the die gap provided by the teeth of the ratcheting mechanism, the fine tuner provides an infinite range of adjustability for setting the die gap. Fine tuning is particularly useful to adjust for the imprecise nature of a real world working environment. First, the fine tuner allows the track and ratchet alignment mechanism to adjust for slight variations in pipe diameter due to pipe manufacturing tolerances. The fine tuner adjusts the die gap alignment for situations where one batch of pipe has a slightly larger or smaller diameter than another batch of the same diameter pipe. Second, the fine tuner allows the track and ratchet alignment mechanism to adjust for wear in the groove of the counter die or bending die. Third, the fine tuner allows the operator to controllably adjust the die pressure for more aggressive bend profiles, such as when the counter-die groove is a more eccentric elliptical shape, or out of round, similar to a curved V-shape. This type of more pronounced bend profile or aggressive bending requires more metal flow in the bend region and higher counter-die pressures to ensure the tube or pipe remains flush with the surface of the counter-die groove.
A still further advantage of the present tube bender is its smooth operation and range of bending motion. The dual hydraulic drive balances the large bending forces and torques, which reduces wear and tear, and maintenance down times. The dual hydraulic drive also allows for 180 degree bends. This range of motion is a significant advantage over bending machines that are limited to 90 degree bends, because these other machines are simply not capable of meeting project requirements. Only unusual bends exceed 180 degrees, and these bends are typically special ordered. Thus, the dual hydraulic drive provides the range of motion needed for a wide array of job situations.
A still further advantage of the present tube bender is its operating efficiency and improved safety. Foot pedals are used to activate forward and reverse movement of the hydraulic drive mechanism. The hands of the operator are free to load and unload pieces of tube or pipe. The foot pedals are connected to the machine by a control cord and can be located a safe distance from the machine. The worker does not have to be close to the machine to turn it on and off. If something is noticeably wrong, the operator can deactivate the hydraulic drive by releasing the foot pedal before approaching the machine.
A still further advantage of the present tube bender is its hydraulic fluid pressure and flow distribution controls. An electric circuit controls the pressure and flow of hydraulic fluid to the two hydraulic cylinders, which eliminates the need of several hydraulic hoses, particularly the unprotected hoses. The remaining hydraulic hoses are inside the frame and housing of the bending machine, where they are protected from being crushed, punctured, cut or otherwise damaged. The elimination of flex hoses also reduces the chance of messy and slippery leaks that can lead to dangerous work conditions. The elimination of the hoses and their connections also reduces the overall cost of the machine.
A still further advantage of the present tube bender is the ease and speed with which dies can be changed. Conventional tools such as commonly available wrenches are used to change the bending die. No tools are needed to change the counter-die. Moreover, die changes do not require the removal of additional parts. This reduces die change down time, and reduces or eliminates possible down time caused by jamming, stripping or damage to fasteners and other components during a die change.
A still further advantage of the present tube bender is its compact size and portability. The machine can be easily transported to a particular area of a construction site or manufacturing plant where tube bending operation are most safely and economically performed. The need for workers to haul large quantities of bulky, heavy tubing or pipe from one end of the site or plant to the other is reduced or eliminated. This improves overall side work productivity, and reduces the possibility of injury.
Other aspects and advantages of the invention will become apparent upon making reference to the specification, claims and drawings.
While this invention is susceptible of embodiment in many different forms, the drawings show and the specification describes in detail a preferred embodiment of the invention. It should be understood that the drawings and specification are to be considered an exemplification of the principles of the invention. They are not intended to limit the broad aspects of the invention to the embodiment illustrated.
The present invention relates to a rotary draw tube bending machine generally designated by reference number 20 in
The tube bender 20 includes several die sets 30, 30a, etc., as shown in
Each counter die 41, 41a has a generally rectangular body with leading and trailing ends 42 and 43. Each counter die 41, 41a has a 2-piece construction with a longer plastic portion proximal the leading end 42, and a shorter bronze portion proximal the trailing end 43. The metal portion forms the working portion of the counter die 41, 41a. Both portions of the counter die 41 form a flat, outer end 44 with a linear concave groove surface 45 formed therein. This uniform shaped groove 45 extends continuously from the leading end 42 to the trailing end 43 of the die. The grooves 35 and 45 of the dies have a uniform diameter or elliptical shape, respectively, to matingly engage a tube or pipe with a specific diameter. The tube bender 20 is designed to bend pipe and tubing 10 up to about 2½ inches in diameter. Although the cross-sectional shapes of the grooves 35 and 45 of the dies 31 and 41 are shown and described as being generally circular or elliptical, and the workpiece 10 is described as being a pipe or tube with a tubular shape, it should be understood that the cross-sectional shapes of the grooves 35 and 45 and workpieces 10 could be square, rectangular, octagon, etc., without departing from the broad aspects of the invention.
During the bending process, the tube or pipe workpiece 10 is pulled or drawn through the groove 45 of the counter-die 41 via the hook 38 of the bending die 31. The path of travel 47 of the workpiece 10 is best shown in
The tube bender 20 includes a spindle assembly 50 that is best shown in
The tube bender 20 also includes a rotating arm assembly 60 that is rotatably secured to one or both of the upper platforms of the frame 21. The arm assembly 60 rotates about the same axis 52 as and independently of the spindle 51. The assembly 60 includes a radial arm 62 that extends outwardly from the spindle 51. The arm 62 includes an upper plate 63 with an upper surface 64 as shown in
The rotating arm assembly 60 has an alignment mechanism 70. The alignment mechanism 70 is formed by a guide track 71, a mating counter die assembly 81 and an adjacent cooperating ratcheting mechanism or ratchet assembly 91. The slide track 71 is formed in the upper plate 63 of the radial arm 62, and is parallel to the radial axis 69. The track 71 forms a recess in the upper surface 64 of the plate 63. This recess or slide track 71 is defined by its upper surface 74 and spaced linear walls 75. One track wall 75 is preferably linearly aligned with the radial axis 69. The track 71 extends linearly from the rear of the radial arm 62 towards the front of the rotating arm. The track 71 includes a linear slot 76 that passes completely through the plate 63. This slot 76 is provided to secure the counter die assembly 81 to the rotating arm 62.
The counter die assembly 81 is slidingly and guidably received by the track 71 of the radial arm 62. The counter die assembly 81 has a base 82 with spaced side walls that flushly engage the walls 75 of track 71. The base 82 includes a locking bolt 83 towards its rear end, which extends through the base and the slot 76 to releasably secure the base and counter die assembly 81 in place at a desired location on the track 71. One side wall of the base 82 has a number of ratchet teeth 84 formed therein. This toothed wall is flush with the track wall 75, and is aligned with the radial axis 69 of the radial arm 62 as shown in
A pivot post 85 is welded to the top surface of the base 82 towards its front end. The pivot post extends upwardly from the base 82, and has a cylindrical shape with a diameter of about two inches that defines its central axis. The central axis of the post 85 is offset 1½ inches from the radial axis 69. A second, longer locking bolt 86 passes through the center of the pivot post 85 and through the slot 76 to releasably secure the pivot post and base 82 along the track 71 in a manner similar to the other bolt 83. The head of each bolt 83 and 86 is flared to abut the upper surface of the base 82 or pivot post 85, respectively. The threaded ends of the bolts 83 and 86 mate with a clamp on the underside of the upper plate 63. These bolts 83 and 86 are tightened down to fixedly secure the counter die assembly 81 to the radial arm 62. When tightened, the longer locking bolt 86 compresses the pivot post 85 against the base 82 to increase the strength of the post and prevent the post from bending during use. The bolts 83 and 86 are loosened to allow the counter die assembly 81 to move along the track 71 between a forward position 87 shown in
The ratcheting mechanism 91 shown in
The ratcheting mechanism 91 preferably includes a fine tuning device 101 best shown in
The ratchet mechanism 91 combines with its fine tuning device 101 to allow an infinite range of alignment positions for the counter die assembly 81 along track 71, and thus provides an infinite range of adjustability for setting the size of the die gap. The fine tuning mechanism 101 is used to adjust and set a tooth 84a recess at a desired initial alignment position for that specific set 30 of bending dies 31 and corresponding counter die 41, such as set 30 and dies 31, 31′, 31″ and 41 or set 30a and dies 31a, 31a′, 31a″ and 41a as in
The counter die assembly 81 includes a swing bracket 110 with a pair of spaced arms 112 that hold the counter die 41. A pivot pin 113 passes through the arms 112 and a hole in the main body of the counter die 31 to pivotally secure the counter die to the swing bracket 110. The spaced arms 112 are joined together at a central portion 114 that defines a central opening. This opening snuggly and rotatably receives pivot post 85. A swing handle 115 is used to swing the bracket 110 into an engaged position 116 shown in
The tube bender 20 is powered by a dual hydraulic drive mechanism 120. This drive mechanism 120 drives the machine 20 between its home position 121 shown in
The cylinders 131 and 141 are double acting so that they can be powered to extend and retract. Each cylinder 131 and 141 has an outer shell 132 or 142 that is pivotally secured at one end to mounting bracket 129 via a mounting pin. Each cylinder 131 and 141 includes a drive rod 135 or 145, respectively. Drive rod 135 is pivotally connected to the drive arm 57 of the spindle assembly 50 by pivot pin 58. Drive rod 145 is pivotally connected to the rotatable or radial arm 62 by a pivot pin 68. During a bending or drive cycle, pressurized hydraulic fluid is delivered to a drive side 136 and 146 of the cylinders 131 and 141 to simultaneously extend the drive rods 135 and 145 from their home position shown in
The desired bend angle for the workpiece 10 is set by an angle limiting device 150 shown in
During the bending cycle and the extension of the drive rods 135 and 145, the triggering groove of the dial 154 rotates towards the limit switch 155. The triggering groove engages the limit switch 155 when the machine 20 reaches the predetermined desired angle of bend, such as the 120° bend angle shown in
The drive mechanism 120 selectively delivers hydraulic fluid to drive cylinders 131 and 141 via an electro-hydraulic control system 200 that is schematically shown in
The solenoid valve 220 has an intake path 222, an internal chamber 224, and three discharge paths 225, 227 and 228. The valve 220 is controlled by its two solenoids 231 and 232, which are in electrical communication with a foot pedal control unit 234 and its two foot pedals 235 and 236. The bending solenoid 231 is hard wired, via limit switch 155, to the bend cycle activating pedal 235. Return solenoid 232 is hard wired to return cycle activating pedal 236. Each pedal 235 or 236 is selectively depressed by the foot of the operator to an activated position. Depressing one of the pedals 235 or 236 energizes its corresponding solenoid 231 or 232, respectively. The limit switch 155 is electrically wired between bend pedal 235 and bend solenoid 231 to break the circuit and flow of electric power to the solenoid 231 when the switch 155 is triggered. The foot pedals 235 and 236 are biased up into a deactivated position. The valve 220 directs pressurized fluid along one of these paths 225, 227 or 228 by use of the pedals 235 and 236. When the tube bending machine 20 is in its home position 121 and activated, but neither foot pedal 235 or 236 is depressed, such as when the machine is not currently being used, then neither solenoid 231 or 232 is activated. In this condition, the valve 220 directs pressurized fluid along idle path 225, which leads back to the reservoir 23 after passing through the filter 23b. No pressurized fluid is delivered to either side 136, 137, 146 or 147 of the hydraulic cylinders 131 and 141, and the machine remains in its home position 121.
During the bending or drive cycle, the operator steps on the bend cycle foot pedal 235 to depress it into an engaged position. This activates the solenoid 231 of valve 220 to direct the flow of pressurized fluid to travel along bend or drive cycle path 227. The pressurized fluid of path 227 flows to a synchronizer or flow divider/combiner 240 that divides and simultaneously delivers the fluid at equal pressure to bending cycle paths 241 and 242. These paths 241 and 242 are fluidly connected via their respective flex hoses 25 to the drive sides 136 and 146 of the cylinders 131 and 141, respectively. This flow of pressurized fluid causes the drive rods 135 and 145 to simultaneously extend at the same rate, which simultaneously rotates the bending die 31 and spindle 51 clockwise 138 and the counter die 41 and arm 62 counter-clockwise 148, both at the same rate of rotation. The foot pedal 235 must remain depressed during the entire bending cycle to keep pressurized hydraulic fluid flowing to the cylinders 131 and 141, until the machine 20 reaches its desired bend position 125 as in
During the return cycle, the operator steps on return cycle foot pedal 236 to depress it into an engaged position. This activates the solenoid 232 of valve 220 to direct the flow of pressurized fluid to travel along return cycle path 228. The pressurized fluid flow of path 228 divides into two equal pressure return paths 251 and 252. These paths 251 and 252 are fluidly connected via their respective flex hoses 26 to the return sides 137 and 147 of the cylinders 131 and 141, respectively. This flow of pressurized fluid causes the drive rods 135 and 145 to simultaneously retract at the same rate, which simultaneously rotates the bending die 31 and spindle 51 counter clockwise and the counter die 41 and arm 62 clockwise 148, both at the same rate of rotation. The foot pedal 236 must remain depressed during the entire return cycle to keep pressurized hydraulic fluid flowing to the cylinders 131 and 141, until the machine 20 reaches its home position 121 as in
Although the process of using the inventive bending machine 20 to bend workpieces 10 should be readily understood based on the above description, the following is provided to assist the reader. Once the appropriate set of dies 30 is determined based on the diameter of the workpiece 10 to be bent, the appropriate bending die 31 is selected with the desired bend radius along with the counter-die 41 for that set 30. The counter-die assembly 81 is pulled back along the track 71 to allow the access space to secure the dies 31 and 41. The selected bending die 31 is secured to the spindle 51, and the selected counter-die 41 is secured to the swing bracket 110 of the counter-die assembly 81.
The counter-die 41 is aligned with the bending die 31 to set the die gap between them as shown in
The quick release 110 is swung to its disengaged position 117, and the workpiece 10 to be bent is loaded, such as is shown in
The desired bend angle is pre-set by rotating the dial 154 until fixed arrow 158 points to the desired bend angle marked on the upper surface of the protractor-like dial 154 as shown in FIGS. 6 and 10A-C. Once the die gap is properly set, the workpiece 10 is properly aligned and secured to the bending machine 20, and the dial 154 is set to the desired bend angle, the operator initiates or actuates the bending or drive cycle of the dual hydraulic drive mechanism 120 and its electro-hydraulic control system 200 by stepping on and depressing foot pedal 235. The pedal 235 remains depressed during the bend cycle, but can be released at any time to instantly stop the bend cycle if desired.
During the bend or drive cycle, the drive rods 135 and 145 simultaneously extend at substantially the same rate and distance from their home position 121 to the desired position 125 that achieves the desired pre-set bend angle on dial 154 as shown in
The bent workpiece 15 is removed from the machine 20 by swinging the quick release 110 to its disengaged position 117 as shown in
The machine 20 is returned to its home position 121 by stepping on the return pedal 236 until the drive rods 131 and 141 of the hydraulic drive 120 reach the home position 121 as in
When a different radius bend is desired for a new workpieces 10 with the same diameter, or for a different location of a previous workpiece 15, the counter die 41 is left in place, but a new bending die 31′ or 31″ must be selected from the die set 30, and placed on the spindle 51. The above process is repeated after readjusting the die gap for the new bending die 31′ or 31″. The locking bolts 83 and 86 are loosened, and the counter-die assembly 81 is slid radially forward or backward in the alignment track 71. The assembly 81 is slid an incremental distance equal to the change in radius between the new bending die 31′ or 31″ and old bending die 31 until the tip 93 of the ratchet 91 is resting in the proper tooth 84a to set the new die gap. The incremental sliding movement of the assembly 81 is easily achieved because the appropriate sliding movement is equal to a multiple of the unit length of the teeth 84. In other words, the unit length of each ratchet tooth 84a is an integer fraction (e.g., 1/1, ½, ⅓, ¼, etc.) of the incremental difference in bend radius between the previous selected 31 and newly selected bending die 31′ or 31″ for that die set 30. This same principal also applies for other die sets 30a made for of the bending machine 20. Thus, even when there is a change in the diameter of the workpiece 10, the incremental adjustment of the die gap is easily achieved by incremental and radial sliding movement of the counter-die assembly 81 along the alignment track 71. Once the counter-die assembly 81 and die gap are properly aligned when the tip 93 of the ratchet 91 rests in the trough of the appropriate tooth 84a, then the locking bolts 83 and 86 are tightened, and the bending, removing and returning steps are repeated.
While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the broader aspects of the invention.
This application is a Continuation of U.S. application Ser. No. 11/724,852 filed Mar. 16, 2007, now U.S. Pat. No. 7,380,430.
| Number | Name | Date | Kind |
|---|---|---|---|
| 3205690 | Roessler, Jr. | Sep 1965 | A |
| 5689988 | Schwarze | Nov 1997 | A |
| 20050263990 | Clute | Dec 2005 | A1 |
| Number | Date | Country | |
|---|---|---|---|
| 20080236234 A1 | Oct 2008 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 11724852 | Mar 2007 | US |
| Child | 12080401 | US |
