Abstract:
Tube bending/crimping apparatus has a frame, a toggle assembly and a carriage assembly. The toggle assembly has overlapping male dies with tapering working tips that form a self-centering wedge. The carriage assembly has a shaft with a pinion that engages a rack on the frame to move the carriage assembly. A handle on the shaft is linked to the shaft by a cam clutch and a plunger, so that when the plunger is engaged, pushing the handle moves the carriage assembly forward. When the plunger is disengaged, the carriage assembly is easily moved back to the starting position. Mechanical stops for the handle assure consistent advancement. A receiving element on the carriage assembly has grooves for several sizes and orientations of tube.

Description:
This application claims the benefit under 35 U.S.C. § 119(e) of the U.S. provisional patent application No. 60/401,369 filed Aug. 6, 2002. 
    
    
     TECHNICAL FIELD 
     The present invention relates to sheetmetal forming apparatus and more particularly to apparatus that forms bends in rectangular tubing. 
     BACKGROUND ART 
     Rectangular tube is used, for example, in downspouts connected to rain gutters to selectively transport rain water downward. Such downspouts often bend inwardly to a building wall from the rain gutter at the eave, then bend downwardly to extend down the wall and then bend outwardly from the wall. Downspouts may require additional bends, as for example, when a lower portion of a wall juts out beyond an upper portion of the wall. It is generally possible to fashion most downspout systems from straight sections of tube combined with mass produced elbows. However, more reliable and esthetically pleasing systems can be built by custom bending tube on site. 
     Rectangular tube is typically bent by a plurality of spaced folds on three sides of the tube. Apparatus for creating the folds includes a female die with an annular groove inside the tube and a toggle assembly with male dies that crimp three sides of the tube into the annular groove. A carriage assembly pushes the tube, folding the crimped portion of tube in the annular groove to form the fold. The bend is formed by alternating crimping and advancing steps. Consistent, esthetic bends require uniform advancement of the carriage assembly between folds. 
     Examples of motorized bending apparatus are disclosed in U.S. Pat. No. 3,670,553 to Nothum et al. and U.S. Pat. No. 3,861,184 to Knudson. Nothum et al. uses a rotating cam and a ratchet mechanism with a rack on the carriage assembly to uniformly advance the tube. Knudson uses an eccentric roller, star follower and a pinion that engages a rack on the carriage assembly to uniformly advance the tube. Manually operated apparatus that is simpler and more portable may be more desirable than motorized apparatus for on site tube bending. 
     U.S. Pat. No. 4,198,842 to Pawlaczyk discloses a manually operated tube bending apparatus with a first handle actuating a toggle assembly and a second handle with a ratchet mechanism connected through a series of gears on the frame and a chain to actuate a carriage assembly. Pawlaczyk does not explicitly disclose any means for assuring uniform advancement of the tube and the second handle must be turned through several rotations to return the carriage assembly to the start position after a tube is bent. U.S. Pat. No. 5,836,194 to Micouleau et al. discloses a manually operated tube bending apparatus with a single handle actuating a toggle assembly and a carriage assembly. The carriage assembly is advanced by an advancing ratchet mechanism with a rack on the carriage assembly that is released when the carriage assembly reaches a forward limit. 
     Precise adjustment of the male dies relative to the female was required in the prior known tube bending/crimping apparatus. The rack on the carriage assemblies of Nothum et al., Knudson, and Micouleau et al. makes each carriage assembly relatively long and thereby the apparatus relatively long. Nothum et al., Knudson, and Pawlaczyk each use a mandrel on the carriage assembly that receives the end of a tube. Such mandrels have to be changed or adjusted for each different size and orientation of tube. 
     A simpler, more compact apparatus than the prior known apparatus would be easier to transport to a work site. Manual apparatus with a carriage assembly that advances a consistent distance and that can easily be moved back to the starting position without multiple turns of a handle is more efficient for an operator to use. A receiving element that receives several sizes and orientations of tube without change or adjustment is also desirable. 
     DISCLOSURE OF THE INVENTION 
     Tube crimping/bending apparatus includes a frame, a carriage assembly movably mounted on the frame, and a toggle assembly. The frame has a base, spaced front and rear plates extending up from the base, a rack connected to the rear plate and extending to the front plate, and a female die, with an annular groove, mounted on the front of the rack. The carriage assembly has a receiving element, a laterally extending carriage shaft carried by the receiving element, a carriage handle, a means for coupling the carriage handle to the carriage shaft, and means for limiting rotation of the carriage handle that provides uniform advancement. The receiving element has grooves that receive several sizes and orientations of tube. The rack extends through an aperture in the receiving element and engages a pinion on the carriage shaft. The means for coupling in a first configuration engages the carriage handle to the carriage shaft in one direction and releases the carriage shaft from the carriage handle in the other direction, and in a second configuration allows the carriage shaft to rotate freely in both directions relative to the carriage handle. The toggle assembly mounts on the front plate and includes a top toggle plate, opposed side toggle plates linked to the top toggle plate, a male die on each of the top and side toggle plates, and a toggle handle that actuates the top and side toggle plates to push the male dies into the annular groove of the female die. The male dies have overlapping working tips that taper to form a self-centering wedge. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Details of this invention are described in connection with the accompanying drawings that bear similar reference numerals in which: 
         FIG. 1  is a perspective view of a tube crimping/bending apparatus embodying features of the present invention, with the dies removed. 
         FIG. 2  is a front elevation view of the apparatus of FIG.  1 . 
         FIG. 3  is a view side elevation of the apparatus of FIG.  1 . 
         FIG. 4  is a top plan view of the apparatus of FIG.  1 . 
         FIG. 5  is a front perspective view of the carriage assembly of the apparatus of FIG.  1 . 
         FIG. 6  is a rear perspective view of the carriage assembly of the apparatus of FIG.  1 . 
         FIG. 7  is an exploded front perspective view of the carriage assembly of the apparatus of FIG.  1 . 
         FIG. 8  is a perspective view of the dies of the apparatus of  FIG. 1  in the open position. 
         FIG. 9  is a front view of the dies of  FIG. 8  in the closed position. 
         FIG. 10  is a sectional view taken along line  10 — 10  of FIG.  9 . 
         FIG. 11  is an enlarged partial view of FIG.  10 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIGS. 1  to  4 , tube crimping/bending apparatus  11  embodying features of the present invention includes a frame  14 , a carriage assembly  15  and a toggle assembly  16 . The frame  11  has a rectangular, U shaped, sheet metal base  19 , a substantially rectangular front plate  20  rigidly mounted on and extending upward from the front of the base  19 , and a spaced, substantially rectangular back plate  21  rigidly mounted on and extending upward from the back of the base  19 . 
     Describing the specific embodiments herein chosen for illustrating the invention, certain terminology is used which will be recognized as being employed for convenience and having no limiting significance. For example, the terms “front”, “back”, “right”, “left” “vertical”, “horizontal, “lateral”, “longitudinal”, “upper” and “lower” refer to the illustrated embodiment in its normal position of use. The terms “inward” and “outward” refer to directions toward and away from the geometric center of the apparatus. Further, all of the terminology above-defined includes derivatives of the word specifically mentioned and words of similar import. 
     Side plates  22  extend upward along opposite sides of the base  19  from the front plate  20  to the back plate  21 . A rectangular tube opening  23 , spaced above the base  19 , extends through the front plate  20  and is sized to receive various sizes of tube. An elongated, toothed carriage rack  26  is affixed to the back plate  21  opposite the tube opening  23 , and extends forwardly through the tube opening  23 . A forwardly extending pin  27  and a threaded hole  28 , below the pin  27 , are provided on the front end of the carriage rack  26 , for mounting a female die, as will be described hereinafter. 
     Parallel, spaced, horizontal support rods  30 , on opposite sides of the carriage rack  26 , extend between and are rigidly attached to the front and back plates  20  and  21 . An elongated limit bar  31  is spaced above the carriage rack  26  and rigidly attaches at opposite ends to the front and back plates  20  and  21 . A plurality of uniformly spaced limit holes  32  extend vertically through the limit bar  31 . A limit pin  33  is provided that fits through the limit holes  32  and extends downward below the limit bar  31 . 
     The carriage assembly  15 , as shown in  FIGS. 5 ,  6  and  7 , includes a receiving element  40 , a carriage shaft  41 , a carriage handle  42 , a means for coupling  43 , that couples the carriage handle  42  to the carriage shaft  41 , and a means for limiting  44 , that limits the stroke of the carriage handle  42 . The receiving element  40  is a substantially rectangular, vertical plate. The receiving element  40  slidably mounts on the frame  14 , under the limit bar  31 , with the carriage rack  26  extending through a horizontal rack aperture  47  that extends through a lower middle portion of the receiving element  40 , and the support rods  30  extending through linear bearings  48  that extend through the receiving element  40  on opposite sides of the rack aperture  47 . A rack guide  50  rigidly mounts to the back of the receiving element  40  below the rack aperture  47 . 
     A plurality of tube receiving grooves  49 , sized and shaped to receive the ends of various sizes and orientations of rectangular tube, are cut into the front of the receiving element  40  around the rack aperture  47 . Spaced, vertical, rearwardly extending right and left carriage side plates  52  and  53  rigidly attach to the back of the receiving element  40 . Aligned carriage shaft bearings  54  extend through the right and left carriage side plates  52  and  53  and aligned stop rod apertures  55  extend through the right and left carriage side plates  52  and  53 , rearward of the carriage shaft bearings  54 . 
     The carriage shaft  41  rotably mounts in the two carriage shaft bearings  54  and extends rightwardly from the right carriage side plate  52  to a carriage shaft right end  57 . A toothed carriage pinion  58  on the carriage shaft  41 , between the right and left carriage side plates  52  and  53 , is keyed or otherwise fixed on the carriage shaft  41  so that the carriage shaft and pinion  41  and  58  rotate together. The carriage pinion  58  is positioned to engage the carriage rack  26  so that when the carriage shaft  41  turns, the carriage assembly  15  moves forwardly or rearwardly on the frame  14 . 
     A cam clutch  60  fits over the carriage shaft  41 , between the right carriage side plate  52  and carriage shaft right end  57 , engaging the carriage shaft  41  when turned in a counter-clockwise direction as viewed from the right side of the tube crimping/bending apparatus  11  while turning freely relative to the carriage shaft  41  when turned clockwise. A hollow, cylindrical cup  61  fits over and is keyed to the cam clutch  60 , and has a right facing, annulus shaped cup face  62  with a plurality of spaced, radially arranged plunger holes  63  that extend into the cup  61 . 
     The carriage handle  42  has a straight, elongated lever arm  65 . A pair of opposed handle bearings  66  extend through the lever arm  65  near one end and a transversely extending hand grip  67  attached to the opposite end of the lever arm  65 . The handle bearings  66  fit onto the carriage shaft  41 , between the cup  61  and carriage shaft right end  57 , so that the carriage handle  42  and carriage shaft  41  rotate freely relative to each other. The handle bearings  66  are secured on the carriage shaft  41  by a fastener  68  on the carriage shaft right end  57 . A cylindrical plunger  69  slidably extends through the lever arm  65  near the handle bearings  66 , and is sized and positioned to fit into the plunger holes  63 , so that when the plunger  69  engages one of the plunger holes  63 , rotation of the carriage handle  42  rotates the cup  61  and the cam clutch  60 . The plunger  69  is biased leftward, toward the cup face  62 , but can be pulled rightward, away from the cup face  62 , to disengage or decouple the carriage handle  42  from the cam clutch  60 . 
     A cylindrical ring  71  fits around the cup  61 , between the right carriage side plate  52  and the lever arm  65 , and rotates freely relative to the cup  61 . The ring  71  has a right face  72  and a spaced left face  73 , with the right face  72  being rigidly attached to the lever arm  65 . A curved stop groove  75  of a selected length extends into the left face  73  and has a first end  77  and a spaced second end  81 . A stop rod  76  extends through the stop rod apertures  55  of the right and left carriage side plates  52  and  53 , and rightwardly from the right carriage side plate  52  into the stop groove  75 , limiting rotation of the carriage handle  42  in the clockwise and counter-clockwise directions. 
     The means for coupling  43 , in the illustrated embodiment, includes the cam clutch  60 , cup  61 , and plunger  69 . When the plunger  69  is engaged, rotation of the carriage handle  42  in the counter-clockwise direction advances the carriage assembly  15  and the carriage handle  42  rotates freely relative to the carriage shaft  41  in the clockwise direction. When the plunger  69  is disengaged, the carriage assembly  15  is easily pushed rearward. Other suitable mechanisms for the means for coupling  43 , may include, by way of example and not as a limitation, a ratchet and sliding gear. The means for limiting  44 , in the illustrated embodiment, includes the stop rod  76  and the stop groove  75  in the ring  71 . Other suitable means for limiting  44  may include, by way of example and not as a limitation, stop pins that directly engage the lever arm  65  at opposite ends of the desired stroke. 
     Referring again to  FIGS. 1  to  4 , the toggle assembly  16  includes a top toggle plate  78 , right and left toggle plates  79  and  80 , a top, right and left male dies  82 ,  83  and  84  mounted on the top, right and left toggle plates  78 ,  79  and  80 , respectively, and a means for actuating  86 , that actuates the top, right and left male dies  82 ,  83  and  84  to crimp a tube. The top toggle plate  78  mounts on the front of the front plate  20  of the frame  11 , above the tube opening  23 , in a vertically slidable fashion and is biased upward. The top toggle plate  78  has a laterally elongated, substantially rectangular shape, extending rightward and leftward of the front plate  20  of the frame  11 . An adjustable upper stop  87 , mounted on the front of the front plate  20  of the frame  11  above the top toggle plate  78  limits upward and downward movement of the top toggle plate. 
     The right and left toggle plates  79  and  80  are vertically elongated, substantially rectangular plates pivotally mounted at the lower ends to the lower end of the front plate  20  of the frame  11  on opposite sides of the tube opening  23 . A pair of elongated spaced toggle links  88  pivotally attach to the top toggle plate  78 , extend downwardly and inwardly, and pivotally attach, one each, near the upper ends of the right and left toggle plates  79  and  80 , such that when the top toggle plate  78  moves downward the toggle links  88  pivot the right and left toggle plates  79  and  80  inward. 
     The means for actuating  86  includes a pair of spaced toggle side plates  90  rigidly mounted to the back of the front plate  20  of the frame  11 , above the limit bar  31 , and a rotably mounted toggle shaft  91  that extends laterally through the toggle side plates  90 . A pair of spaced, vertical, toothed toggle racks  93  rigidly mount to the back of the top toggle plate  78  on opposite sides of the front plate  20  of the frame  11 , and mesh with toggle pinions  94  that are rigidly attached to the toggle shaft  91 . Other suitable means for actuating  86  may include a plunger and link arrangement. A toggle handle  96  includes an elongated lever arm  97  that attaches at one end to the left end of the toggle shaft  91  and has a laterally extending hand grip  98  attached to the opposite end. 
     Referring to  FIGS. 7  to  10 , the female die  100  is sized and shaped to fit into the tube selected to be bent, having a substantially rectangular frontal profile with radiused corners. The female die includes an annular groove  101  that extends around at least the top and both sides. An alignment aperture  102  and a fastening aperture  103 , below the alignment aperture, each extend through the female die  100 . The female die  100  fastens onto the front end of the carriage rack  26  with the pin  27  extending through the alignment aperture  102 , and with a threaded fastener  104  extending through the fastening aperture  103  into the threaded hole  28 . 
     The top, right and left male dies  82 ,  83  and  84  are each a substantially flat plate. The top, right and left male dies  82 ,  83  and  84  overlap when mounted in the top, right and left toggle plates  78 ,  79  and  80 , with the right and left male dies  83  and  84  behind the top male die  82 . The top male die  82  has a generally downward pointing working tip  105  shaped to crimp the top and upper corners of a tube, and sized and shaped to fit into the annular groove  101  of the female die  100 . The right mail die  83  has a generally leftward pointing working tip,  106  shaped to crimp the right side and right upper corner of a tube, and sized and shaped to fit into the annular groove  101  of the female die  100 . The left male dies  84  has a generally rightward pointing working tip  107  shaped to crimp the left side and left upper corner of a tube, and sized and shaped to fit into the annular groove  101  of the female die  100 . The working tip  105  of the top male die  82  tapers rearwardly while the working tips  106  and  107  of the right and left male dies  83  and  84  taper forwardly so that the overlapping portions form a wedge that self-centers the top, right and left male dies  82 ,  83  and  84  in the annular groove  101  of the female die  100 . 
     Operation of the apparatus  11  commences with selection and mounting of the correct female die  100  and top, right and left male dies  82 ,  83  and  84  for the size and orientation of the selected tube. The limit pin  33  is inserted into the limit hole  32  in limit bar  31  corresponding to the selected number of folds. The cylindrical plunger  69  on the carriage handle  42  is pulled out and the carriage assembly  15  is pushed back until the limit pin  33  stops the receiving element  40 . A tube is inserted into the tube opening  23 , around the female die  100 , and into the receiving groove  49  on the receiving element  40 . The cylindrical plunger  69  on the carriage handle  42  is released into one of the plunger holes  63  of the cup  61  to couple the carriage handle  42  to the cam clutch  60 , so that actuation of the carriage handle  42  will advance the tube. The toggle handle  96  and the carriage handle  42  are pulled alternately, crimping then advancing and folding the tube, until the receiving element  40  reaches the front plate  20  of the frame  14  to form a plurality of folds and thereby a bend in the tube. 
     The above described tube crimping/bending apparatus  11 , with the carriage rack  26  attached to the frame  14  and the carriage pinion  58  on the carriage assembly  15 , is compact and mechanically simple. The means coupling  43  makes operation easy and the means for limiting  44  assures consistent folds. The receiving grooves  49  on the receiving element  40  eliminate the need to change mandrels. The overlapping, tapered, self-centering working tips  105 ,  106  and  107  of the top, right and left male dies  82  minimize the need for precise adjustment of the male dies. 
     Although the present invention has been described with a certain degree of particularity, it is understood that the present disclosure has been made by way of example and that changes in details of structure may be made without departing from the spirit thereof.