Abstract:
One-step offset bender for speed and accuracy in offsetting pipe or other materials. The offset bender ( 100 ) includes a base ( 110 ) on which is mounted a fixed shoe support ( 130 ) and a traveling shoe support ( 160 ). The fixed shoe support fixedly holds a first shoe assembly ( 200 ), and the traveling shoe support holds a second shoe assembly ( 200′ ) that can be moved vertically and horizontally. The offset bender simultaneously produces two, aligned, equal and opposite bends in conduit by pressing down on the second shoe assembly ( 200′ ). The conduit shoe assemblies include a plurality of conduit shoes that can be selectively aligned to accommodate the desired conduit. The fixed shoe support is pivotally attached to the base, and the traveling shoe support is removable, such that the bender may be folded for easy transport. A motor ( 361 ) or other power system may be used to facilitate making the bend.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application also claims the benefit of Provisional Applications No. 60/411,573, filed Sep. 17, 2002, and No. 60/381,744, filed May 17, 2002, the benefit of which is hereby claimed under 35 U.S.C. § 119. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to offset benders and, more specifically, to one-step offset benders for pipe and other materials. 
     BACKGROUND OF THE INVENTION 
     Conduit bending is one of the fundamental tasks of the electrical construction industry. For example, conventional electrical wiring installations may use EMT (electrical metallic tubing), galvanized steel conduit, or intermediate conduit for protecting runs of wiring. Installation of the conduit generally requires following a path that may be irregular and may include protuberances and other irregularities that must be negotiated. Very frequently, a step-type bend is required, wherein a straight length of conduit is bent twice such that the end portions of the conduit are parallel but offset. This is commonly referred to as an “offset bend.” It will be appreciated that an offset bend typically requires two equal and opposite bends in the conduit. 
     When the conduit must be bent to generally go around or over an obstacle in an otherwise linear path, two complementary offset bends are made, producing what is commonly called a “saddle bend.” A saddle bend generally requires four bends in the conduit, which bends are all equal, with two bends opposite in direction to the other two bends. 
     Often a number of parallel runs of conduit are required. In such cases, it is desirable that the offset bends for all of the parallel runs be very nearly identical, in order to have an easily followed and aesthetically pleasing result. Producing a good, consistent offset bend, however, requires practice, and can be difficult and time-consuming even for experienced installers. Moreover, if an error is made in an offset bend or saddle bend, the conduit may be rendered unusable. 
     With a conventional bender, a mechanic in the trade typically bends one end of the pipe a selected amount, and then calculates the appropriate the location and angular amount for a second bend that must be accomplished to achieve a specified offset, while accounting for the “conduit shrinkage” caused by the bent portion of the conduit. This is a time-consuming process and can be less than a science. It may take hundreds of hours to learn the skill to make a good offset bend. Another problem with conventional benders is that if the pair of bends are not appropriately aligned, i.e., precisely at 180 degrees opposite, you get what is called a “dog leg,” wherein the offset end is not parallel to the starting end. Even when everything is done right and efficiently, it simply takes time to carefully produce two separate bends in a conduit. 
     A conventional conduit bender includes a conduit shoe having a curved groove that is sized generally to receive the conduit, and a ring or hook element near the end of the groove that is adapted to hold the end of the conduit in alignment during the bending process. An example of a conduit shoe is disclosed in U.S. Pat. No. 4,269,056 to Kozinski. As disclosed by Kozinski, the conduit shoe, or conduit bender, has a rocker base portion formed by a pair of laterally spaced, curved sidewalls that define a longitudinally extending conduit-receiving groove therebetween. A hook is formed at one end of the rocker base portion. Other suitable, somewhat similar conduit shoe members for bending conduit are in common use and are well known in the field. Such suitable shoes are simply referred to as “conduit shoes” herein. 
     It will also be appreciated that, although the present invention is described with reference to conduit, it is also suitable for producing offset bends—including, for example, saddle bends—in other tubular materials or other materials, such as metal pipe for water, gas, or the like. Producing such bends in other tubular materials may be particularly important in applications where space is tight and/or the desired routes for such materials are not straight and/or regular, such as in boats, ships, and other vehicles. It should be understood that the term “conduit,” as used herein, includes any metal tubular or other-shaped material and, in particular, is not restricted to tubing used for housing wiring. 
     Although devices for producing offset bends in one step in pipe, conduit, and other materials have been proposed, prior art offset benders have one or more disadvantages. For example, they often are not suitable for producing large offset bends (over one inch) in a single step; they may require mechanical assistance and/or leverage; they cannot accommodate different-sized materials; they often are large and difficult to transport to a construction site; they can be difficult to use; they may not permit easy removal of the bent pipe or conduit; and may not produce repeatable or sufficiently accurate offset bends. 
     While conventional offset benders may be suitable for the particular purpose to which they address, they are not as suitable for speed and accuracy in offsetting pipe or other materials. In these respects, the one-step offset bender, according to the present invention, substantially departs from the conventional concepts and designs of the prior art, and in so doing, provides an apparatus primarily developed for the purpose of improving speed, accuracy, and portability in offsetting pipe or other materials. 
     SUMMARY OF THE INVENTION 
     In view of the foregoing disadvantages inherent in the known types of offset benders now present in the prior art, the present invention provides a new one-step offset bender construction wherein the same can be utilized for speed and accuracy in offsetting pipe or other materials. 
     The general purpose of the present invention, which will be described subsequently in greater detail, is to provide a new one-step offset bender that has many of the advantages of conventional conduit benders and novel features that result in a new one-step offset bender that is easy to use, easy to manufacture, and easily transportable. 
     To attain this, the present invention generally comprises: (i) a base; (ii) a first shoe support; (iii) a first shoe assembly attached to the first shoe support, the first shoe assembly including at least one conduit shoe; (iv) a second shoe support that is movable horizontally with respect to the first shoe support; and (v) a second shoe assembly that is movable vertically with respect to the first shoe assembly, the second shoe assembly including at least one conduit shoe. The conduit shoes include a curved radius with a curved groove and a hook arm, as are known in the art, that hold one end of the conduit in a substantially horizontal position. 
     In the preferred embodiment, each shoe assembly includes a plurality of shoes of differing sizes that are pivotally and lockably mounted to the supports, allowing the user to easily select a desired size. 
     In the preferred embodiment, the frame includes a horizontal rail that movably supports the second shoe support, and the second shoe assembly is mounted on a vertical rail, whereby the second shoe assembly may be moved generally toward and away from the first shoe assembly, and may be moved vertically with respect to the first shoe assembly. 
     In another aspect of the preferred embodiment, two or more different sized conduit shoes are mounted on opposite ends of a shaft to allow the shoe size to be changed by pulling a pin and spinning the arm 180 degrees and replacing the pin. A single set of shoes may be used with different sized. 
     In yet another embodiment of the invention, a motor is used to provide motive power for vertically moving the second shoe assembly. The motive power may be provided with and electric motor, hydraulically, or the like. 
     In this respect, before describing one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of the description and should not be regarded as limiting. 
     An object of the present invention is to provide a one-step offset bender for speed and accuracy in offset bending of pipe or other materials. 
     Another object of the present invention is to provide a one-step offset bender that makes a straight or true offset in a pipe, conduit, or flat stock in one bend. One of the problems to overcome was that the overall length gets shorter as the material is bent. 
     Another object is to provide a one-step offset bender that will save time on the job. It may incorporate a built-in guide, so one can read the guide instead of getting out a measuring tape. 
     Another object is to provide a one-step offset bender that will provide a more uniform outcome on parallel runs of pipe. 
     Another object is to provide a one-step offset bender that, for smaller uses, could be transported and handled by one person, put in a truck, and used on a small site. 
     Other objects and advantages of the present invention will become obvious to the user, and it is intended that these objects and advantages are within the scope of the present invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein: 
     FIG. 1 is a perspective view of a first embodiment of an offset bender according to the present invention; 
     FIG. 2 is a partially-exploded perspective view of the base of the offset bender shown in FIG. 1; 
     FIG. 3 is a partially-exploded perspective view of the fixed shoe support of the offset bender shown in FIG. 1; 
     FIG. 4 is a partially-exploded perspective view of the movable shoe support of the offset bender shown in FIG. 1; 
     FIG. 5 is a perspective view of the offset bender shown in FIG. 1, showing a user moving the offset bender on its wheels; 
     FIG. 6 is a perspective view of the offset bender shown in FIG. 1, shown disassembled and folded for transport; 
     FIG. 7A is a perspective view of the offset bender shown in FIG. 1, with a length of conduit inserted, in position for bending; 
     FIG. 7B is a perspective view of the offset bender shown in FIG. 7A, after an offset bend has been made in the length of conduit; and 
     FIG. 8 is a perspective view showing a second embodiment of an offset bender according to the present invention, wherein a motor drive is coupled to the movable shoe assembly. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A currently preferred embodiment of the present invention will now be described, with reference to the figures, wherein like reference characters denote like elements. Referring now to FIG. 1, a one-step offset bender  100  according to the present invention is depicted. The major components of the offset bender  100  are a generally horizontal base  110 , a fixed shoe support  130  that supports a first shoe assembly  200 , and a traveling shoe support  160  that supports a second shoe assembly  200 ′. 
     Referring now to FIG. 2, a partially-exploded perspective view of the base  110  of this embodiment is shown. The base  110  includes a pair of generally horizontal, parallel rails  112  supported by a front leg assembly  114  and a rear leg assembly  118 . The rails  112  include outboard longitudinal guides  121  disposed on the bottom of the rails  112 . The front leg assembly  114  includes a transverse member  116  and two short vertical supports  115  that extend upwardly from the transverse member  116 , and fixedly attach to the bottom of a corresponding rail  112 . The rear leg assembly  118  includes a transverse member  120  and two vertical supports  119  that attach to the outboard sides of each rail  112 . A pair of wheels  124  are rotatably attached to the rear leg assembly  118  with axles  122 , and are positioned such that the transverse members  116 ,  120  rest securely on the ground when the offset bender  100  is positioned as shown in FIG.  1 —but the base  110  can be lifted from the forward end to allow the wheels  124  to engage the ground, whereby the offset bender  100  can be easily moved about on the wheels  124 , as shown in FIG. 5. A removable locking pin  109  is insertable into the locking pin aperture  123  on the base  110 . 
     A first pivot aperture  113  is provided near the front end of the base  110  and a pivot or rod  111  is slidably inserted through the pivot aperture  113  after properly positioning the fixed shoe support  130  (see FIG. 1) to attach the fixed shoe support  130  to the base  110 . Fastening hardware  108  secures the rod  111  in place. 
     Transversely aligned locking cam assemblies  125  are attached to each rail  112 . The locking cam assembly  125  includes a disk  126  rotatably disposed in a metal hoop  127 , the disk  126  having a cam aperture  128  near the edge of the disk  126 . A setscrew  129  is provided through the metal hoop  127  to lock the disk at a desired orientation. A rod  117  is slidably inserted through the cam apertures  128  to releasably attach the fixed shoe support  130  (see FIG. 1) to the base  110 . A pair of locking pins  109  secures the rod  117  in place. 
     Referring now to FIG. 3, a partially-exploded view of the fixed shoe support  130  is shown. The fixed shoe support  130  includes a first arm  132  pivotally connected to a second arm  136 . The first arm  132  is adapted to be pivotally attached to the base  110  with the pivot rod  111  (see FIG. 2) through pivot aperture  113 ′. The first arm  132  is pivotally attached to the second arm  136  at the opposite end. The first arm  132  includes an angled portion  134  is provided near the top of the first arm  132  to accommodate the first shoe assembly  200 , discussed in detail below. The second arm  136  is pivotally attached to the first arm  132  at one end, and is adapted to releasably engage the locking cam assemblies  125  (see FIG. 1) at the cam apertures  128  (see FIG. 2) through aperture  128 ′, such that the first and second arms  132 ,  136  form an inverted V-shaped support. 
     The first shoe assembly  200  is pivotally attached near the top of the first arm  132  of the fixed shoe support  130 . The first shoe assembly  200  includes a first conduit shoe  202  and a second conduit shoe  204  mounted on opposite ends of a conduit shoe shaft  206 . The first and second conduit shoes  202  and  204  are of different sizes and, in the preferred embodiment, the first conduit shoe  202  is sized to bend ½-inch EMT conduit, and the second conduit shoe  204  is sized to bend ¾-inch EMT conduit, although it will be readily apparent that conduit shoes of different sizes could alternatively be used. The first shoe assembly  200  is pivotally attached to the first arm  132  with a pivot rod  208  that passes through an aperture  207  centrally disposed in the conduit shoe shaft  206  and through a corresponding aperture  137  in the fixed shoe support  130 . The pivot rod  208  may be held in place with conventional fastening hardware  218 . A pair of locking apertures  209  is provided, one near each end of the conduit shoe shaft  206 , that is positionable over a corresponding locking aperture  139  in the fixed shoe support  130 , such that a locking pin  210  can be inserted to rotationally lock the first shoe assembly  200  in either of two positions. For example, when the first shoe assembly  200  is locked in the first position, the user can remove the locking pin  210 , spin the first shoe assembly  200  by 180 degrees, and re-insert the locking pin  210  to lock the first shoe assembly in a second position. 
     It should now be appreciated that the first shoe assembly  200  provides two different-sized conduit shoes  202 ,  204 , and that the user can selectively lock either shoe into the desired position, depending on the size of conduit to be bent. It is also contemplated that with minor modifications that would be obvious to persons of ordinary skill in the art, more than two different sized conduit shoes could be incorporated into the first shoe assembly. Alternatively, the first shoe assembly  200  may be removably attached to the fixed shoe support  130 , whereby a user could select from a variety of different shoe assemblies to accommodate a particular application and conduit size. For example, conduit shoes having a different bend radii may be desired for a particular application. 
     The purpose of the cam assemblies  125  should now be clear. The off-center cam apertures  128  in the lockable, rotatably mounted disks  126  permit user to selectively adjust, or fine tune, the position of the first shoe assembly  200  to permit very accurate conduit bending to be accomplished. Although the cam assemblies  125  are shown, it will be readily apparent that other adjustment means, such as a sliding bar assembly or the like, may alternatively be used to permit accurate positioning of the first shoe assembly  200 . 
     Referring now to FIG. 4, a partially-exploded view of the traveling shoe support  160  is shown. The traveling shoe support  160  includes a truck assembly  162  that engages the rails  112  of the base  110  (see FIG.  1 ). In the disclosed embodiment, the truck assembly  162  includes sets of four wheels  164  arranged on each side of the traveling shoe assembly  160 . Each set of four wheels  164  includes two upper and two lower wheels  164 , the upper and lower wheels spaced to receive one of the rails  112  therebetween. The traveling shoe support  160  is therefore supported by the rails  112 , and can move back and forth along the rails  112 . In particular, the traveling shoe support  160  can move toward, and away from, the fixed shoe support  130 . It will be apparent from FIG. 1, that the truck assembly  162  is maintained centered on the rails  112  by the outboard longitudinal guides  121 . Although the preferred truck assembly utilizes wheels  164  to move along the rails  112 , it is also contemplated that alternative mechanisms to allow translation could alternatively be used, such as a slide or a geared assembly. 
     A first upright member  170  extends upwardly from the truck assembly  162 . A wheeled platform  172  is movably disposed on the first upright member  170 , the wheeled platform  172  having four wheels  174  that are spaced to receive the first upright member  170  therebetween. The wheeled platform  172  can move vertically, guided by the first upright member  170 . A second shoe assembly  200 ′ is movably disposed on the wheeled platform  172 . The second shoe assembly  200 ′ can therefore move horizontally along the rails  112  by moving the entire traveling shoe support  160 , and can move vertically along the upright member  170 . The second shoe assembly  200 ′ is preferably identical to the first shoe assembly  200  and, in particular, includes conduit shoes  202 ′ and  204 ′ connected with a conduit shoe shaft  206 ′ and pivotally attached to the wheeled platform  172  with a pivot rod  208 ′ disposed through the apertures  207 ′ and  177  and attached with the fastening hardware  218 ′. A removable locking pin  210 ′ is provided to lock the second shoe assembly  200 ′ in either of two positions that are 180 degrees rotated, through one of the second shoe assembly  200 ′ apertures  209 ′ and aperture  179  in the wheeled platform  172 . A biased latch assembly  176  is attached to the wheeled platform  172 , and a corresponding catch  178  is provided at the top of the first upright member  170 , such that the wheeled platform  172  can be releasably latched near the upper end of the first upright member  170 . 
     A second upright member  180  also extends upwardly from the truck assembly  162 , generally parallel to the first upright member. The second upright member  180  preferably includes a gauge or measuring apparatus  182  that is positioned to have zero aligned with the top of the conduit shoe  202  or  204  on the first shoe assembly  200 , such that the top of a conduit (not shown) inserted for bending in the offset bender  100  (see FIG. 6) will be positioned at the top of the measuring apparatus  182 . A cross support  175  connects the first and second upright members  170 ,  180  at the top for strength and stability. 
     Referring again to FIG. 1, it will now be appreciated that the fixed shoe support  130  is pivotally attached near one end of the base  110 , and also releasably attached to the locking cam assemblies  125 . The traveling shoe support  160  is rollably mounted on the rails  112 , such that it can move toward or away from the fixed shoe support  130 . The removable locking pin  109  at the far end of the base  110  prevents the traveling shoe support  160  from disengaging from the base  110 . The offset bender  110  is therefore easily foldable, as shown in FIG. 6 (as compared with FIG.  1 ). The user simply removes the locking pin  109  near the far end of the base  110  and rolls the traveling shoe support  160  off of the base  110 . Then user then removes the locking pins  109  at each locking cam assembly  125  and removes the rod  117 , to release the second arm  136  of the fixed shoe support  130  from the base  110 . The entire fixed shoe support  130  can then pivot toward the base  110 . (The rod  117  and locking pins  109  are shown reinserted into their respective apertures for convenient access.) The offset bender  110  can therefore be easily folded for transporting to the work site. 
     The operation of the offset bender  100  for bending pipe or conduit  90  will now be described, with reference to FIGS. 7A and 7B. FIG. 7A shows the offset bender  100  with a length of unbent conduit  90  properly inserted into the second conduit shoe  204  of the first shoe assembly  200 , and into the second conduit shoe  204 ′ of the second shoe assembly  200 ′. The traveling shoe assembly  160  is pre-positioned such that the distance between the second conduit shoes  204  and  204 ′ is at the desired spacing (often called the “star-to-star” length) for the offset bend. 
     The top of the conduit  90  prior to bending is disposed near the top of the measurement apparatus  182 . The conduit  90  is now in position for receiving an offset bend. The user simply pulls down on the second shoe assembly  200 ′ until the desired bend has been achieved, as shown in FIG.  7 B. The desired offset bend is easily determined by looking at the end of the conduit  90  near the measuring apparatus  182  and pulling the second shoe assembly  200 ′ until the desired offset is achieved. It can be seen by comparing FIGS. 7A and 7B, that the traveling shoe support  160  must move towards the fixed shoe support  110  during the bend to accommodate the “shrinkage” or loss of longitudinal length resulting from the bend in the conduit  90 . It will be appreciated that if a different diameter conduit must be bent, the user can simply pull the locking pins  210 ,  210 ′ from the respective first and second shoe assemblies  200 ,  200 ′, spin the shoe assemblies  200 ,  200 ′ by 180 degrees, and reinsert the locking pins  210 ,  210 ′. Also it should be appreciated that the user can produce a single bend in the conduit  90  by inserting the conduit in the shoe  204  of the first shoe assembly  200  and pulling down on the end of the conduit, or moving the second shoe assembly  200 ′ downwardly on the conduit without inserting the conduit into the shoe  204 ′. 
     It is also contemplated that a lever means (not shown) may be provided between the first and second shoe assemblies  200 ,  200 ′ to facilitate bending the conduit  90 . For example, a pair of eye screws (not shown) may be installed on the first and second shoe assemblies  200 ,  200 ′ such that a length of pipe or rod (not shown) may be inserted through the eye screws to gain mechanical leverage for pulling down on the second shoe assembly  200 ′. 
     An alternative embodiment of an offset bender  300  according to the present invention is shown in FIG.  8 . The offset bender  300  is substantially identical to the offset bender  100  described above, except as discussed below. For brevity a description of the common elements is not repeated here. The first upright member  370  of the traveling shoe support  360  is a motor-driven screw, driven by a motor  361  disposed on the truck assembly  362 . The second shoe assembly  200 ′ is attached to a movable platform  372  that engages the motor-driven screw  370  and is guided by the vertical member of the traveling shoe support  360 , such that operation of the motor  361  will cause the motor-driven screw  370  to turn, thereby moving the movable platform  372  and the second shoe assembly  200 ′ up or down, depending on the direction the screw  370  is turned. This embodiment of the offset bender  300  provides a power assist to the user for bending the pipe or conduit, and therefore is particularly suitable for bending very stiff tubing and for applications where a lot of bends must be made, wherein a user may become fatigued from manually bending the tubing. Although a straightforward power-assisted apparatus is shown, it will be readily apparent that other power assist mechanisms, as are well-known in the art, may alternatively be used. For example, the moving platform  372  may be mounted with geared, motor-driven wheels that engage corresponding teeth on an upright member, or pneumatic or hydraulic powered systems may be utilized. For larger pipe, a power-driven ram, screw, gear, sprockets, and chain, or other power assist element may be used to facilitate bending the pipe. 
     While the preferred embodiment of the invention has been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention.