Patent Document

FIELD OF THE INVENTION 
   The present invention relates to a hand tool especially adapted for use in attaching a corner connector element to a sheet metal duct flange, and a method employing the same. 
   BACKGROUND OF THE INVENTION 
   Various duct-connecting systems are known for connecting sections of heating and air conditioning sheet metal ducts. The duct sections may be formed of galvanized sheet steel, typically of 18-26 gauge thickness. Commonly, the duct sections are of rectangular cross-sectional shape and have integral transverse flanges at an end. 
   Well-known examples of such transverse duct flange connecting systems include the Transverse Duct Connector (TDC) and Transverse Duct Flange (TDF) systems. In  FIG. 1 , there appears a fragmentary view of a rectangular duct section  10  employing an exemplary TDC or TDF type flange system. The duct section  10  includes transversely extending flange members  12  extending from each of the duct walls  14 . Each flange member  12  includes a first portion  16  extending perpendicular to the elongate or axial direction of the duct. The radially outward edges of the flanges  12  are bent back to form an upstanding, axially-extending lip  18  which extends parallel to the sides  14  of the duct section  10  from which the flanges transversely project to form a generally channel-shaped flange. In the well-known TDC/TDF system, each of the lips  18  is formed of a fold of metal to double the effective thickness of the lip  18  to provide additional reinforcement. 
   Because the sides  14 , transverse flange portion  16 , and lips  18  of each duct section  10  are all integrally formed from a single sheet of metal, the flange members  12  do not extend around the corners of the duct sections. Accordingly, right-angle shaped corner connectors  20  having apertures  22  adapted to receive fasteners, such as bolts, are used as the primary means of connecting adjacent duct sections together. The corner connectors each have a pair of legs  24  intersecting at right angles. The two perpendicular legs of the corner connector  20  are seated upon the surfaces of adjacent, mutually perpendicular flange members  12  projecting from adjacent sides  14  of the duct section  10 . A peripheral rib or ridge  26  may be formed in the duct wall  14  to facilitate seating or a snap-fit retention of the corner connector  20  within the flange  12 . A side cross-sectional view of a corner connector  20  seated within a flange  12  is shown in  FIG. 2 . 
   Although only a single corner of a single duct section  10  is shown for ease of illustration, it will be recognized that four corner angle fasteners  20  will be seated on the flanges at each end of a duct section  10  for coupling to another duct section. Likewise, four additional corner angle fasteners  20  will be seated within like flanges on the other duct section to be joined. Bolts are then passed through each pair of facing corner angle fasteners, thereby compressing the flanges at the abutting ends of the joined duct sections. 
   To prevent the corner connectors from becoming dislodged from the transverse duct flange, e.g., during transport or handling, it is common to secure the corner connectors  20  to the flanges  12  by bending the upstanding lips  18  projecting from the flanges over the corresponding aligned portions of the legs  22  of the corner connectors to form a crimped connection  26  between the flange  12  and corner connector  20 . Commonly, a hammer or mallet is used to bend a portion of the flange lip  18  over the right angle connector legs  24 . U.S. Pat. No. 4,713,959 discloses a tong- or pliers-like hand tool having specially shaped jaws for bending the upstanding flange lips of a transverse duct flange over the legs of the corner connectors. The tool disclosed in U.S. Pat. No. 4,713,959 is said to overcome noise and efficiency problems associated with pounding over the flange lips using a hammer. 
   A disadvantage of the above-mentioned pliers-type of crimping tools is that they require that a high amount of force be applied by the user, particularly when used with ducts formed of heavier gauges of sheet metal, such as 18 or 20 gauge. The force required is such that some operators lack sufficient physical strength to perform a bending or crimping operation. Even where the operator possesses a sufficient degree of strength to perform a crimping operation with a pliers-type crimping tool, the stresses applied to the tool due to the degree of force required to bend over the flange lips makes such prior art tools highly susceptible to breakage. 
   What is needed, therefore, is a crimping tool and method for securing a corner connector to a transverse duct flange which is less physically demanding on the operator and which is suited for use with all gauges of sheet metal, including heavier gauges such as 18 and 20 gauge thicknesses. The present invention contemplates an improved duct flange crimping tool and method which overcome the above-referenced limitations and others. 
   SUMMARY OF THE INVENTION 
   In one aspect, an apparatus is provided for crimping a corner connector to a rectangular duct section having a transverse duct flange with a transverse portion extending transversely with respect to an axial direction of the duct and a lip portion extending from the transverse portion in the axial direction. The apparatus includes a head defining a jaw opening sized to receive the transverse duct flange, the head having an inner jaw member, an outer jaw member in spaced-apart, facing relation to the inner jaw member, and an intermediate jaw member extending between the inner and outer jaw members. A first handle extends from the head and a second handle is pivotally attached to the head and is movable between a first, open position and a second, closed position. A plunger is slidably received within a plunger orifice formed within the inner jaw member and is mechanically coupled to the second handle wherein pivoting movement of the second handle from the open position to the closed position causes sliding movement of the plunger from the inner jaw member toward the outer jaw member. The plunger and plunger orifice are positioned within the inner jaw member so that, upon placement of a transverse duct flange within the jaw opening, movement of the second handle from the open position to the closed position will cause a bending over of the transverse duct flange lip portion. 
   In another aspect, a method for securing a corner connector within a transverse duct flange of a rectangular duct section is provided. First and second legs of a corner connector are placed within first and second adjacent flange portions of the rectangular duct section, each of the flange portions including a transverse portion and an upstanding lip, the transverse portion extending transversely between a duct wall and the lip. A crimping tool is provided, the crimping tool being of a type having a head defining a jaw opening sized to receive the transverse duct flange. The head has an inner jaw member, an outer jaw member in spaced-apart, facing relation to the inner jaw member, and an intermediate jaw member extending between the inner and outer jaw members. A first handle extends from the head and a second handle is pivotally attached to the head and is movable between a first, open position and a second, closed position. A plunger is slidably received within a plunger orifice formed within the inner jaw member and is mechanically coupled to the second handle wherein pivoting movement of the second handle from the open position to the closed position causes sliding movement of the plunger from the inner jaw member toward the outer jaw member. The plunger and plunger orifice are positioned within the inner jaw member so as to be in aligned, facing relation with at least a portion of the lip when the transverse duct flange is received within the jaw opening. For each corner connector leg, the transverse duct flange is inserted into the jaw opening and the second handle is moved to the closed position relative to the first handle so as to cause movement of the plunger member transversely toward the outer jaw member, thereby bending a portion of the upstanding lip over an aligned portion of the corner connector leg. 
   In more limited aspects, the apparatuses and methods described herein are adapted for use with TDC and/or TDF transverse duct flange systems. 
   One advantage of the present invention resides in the ease of performing a crimping operation for all sheet metal thicknesses. The present invention provides increased mechanical advantage over the prior art pliers-type crimping tools and requires less physical strength on the part of the user and provides increased ease of use and efficiency as compared to the prior art tools. 
   Another advantage of the present invention is that it does not rely on a scissor-like action to perform a bending or crimping operation. As such, the stresses placed on the tool are reduced, thereby reducing the susceptibility of the tool to breakage. 
   Other benefits and advantages of the present invention will become apparent to those skilled in the art upon a reading and understanding of the preferred embodiments. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS  
     The invention may take form in various components and arrangements of components, and in various steps and arrangements of steps. The drawings are only for purposes of illustrating preferred embodiments and are not to be construed as limiting the invention. 
       FIG. 1  is a fragmentary view of an exemplary prior art transverse duct flange having a corner connector secured therein by crimping. 
       FIG. 2  is cross-sectional view of the exemplary prior art corner connector within the transverse flange of  FIG. 1 , prior to bending or crimping the flange upstanding lip. 
       FIG. 3  illustrates a first embodiment crimping tool adapted to bend the upstanding lip of a transverse duct flange over a corner connector received therein. 
       FIG. 4  depicts the crimping tool embodiment of  FIG. 4  with the handles in the closed position. 
       FIG. 5  depicts a crimping tool in accordance with a second embodiment. 
       FIG. 6  depicts a crimping tool in accordance with a third embodiment. 
       FIG. 7  depicts a crimping tool in accordance with a fourth embodiment. 
       FIG. 8  depicts a crimping tool in accordance with a fifth embodiment. 
       FIG. 9  depicts a crimping tool in accordance with a sixth embodiment. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
   Referring to  FIGS. 3 and 4 , there appears a first embodiment crimping tool  30  having a head  32  defining a jaw opening  34 . The jaw opening  34  is bounded on three sides by an inner jaw member  36 , an outer jaw member  38 , and an intermediate jaw member  40 , which is intermediate the inner and outer jaw members. The inner and outer jaw members  36  and  38 , respectively, include substantially parallel, facing surfaces which are spaced apart a distance D which is sufficient to receive, and preferably slightly larger than, the transverse extent of the transverse duct flange member  12  to be crimped. As used herein, the term “transverse duct flange” includes any rectangular duct flange of a type having a first portion extending transversely with respect to the axial direction of the duct and a second upstanding lip extending therefrom. The preferred types of transverse duct flange for use with the present invention are the well-known TDC and/or TDF types, although it will be recognized that the present invention may also be used with any other type of transverse duct flange having an upstanding peripheral lip that may be bent or crimped onto a corner connector. In the preferred TDC/TDF crimper embodiment, the distance D is approximately 1.5 inches (3.8 cm). 
   A first handle  42  extends from the head  32  and is rigidly affixed relative thereto. A second handle  44  is pivotally attached to the head  32  about a pivot pin  46  and is movable between an open position (see  FIG. 3 ) and a closed position (see  FIG. 4 ). If desired, hand grips  48 , such as tubing, padding, or other hand grip material may be provided on all or part of the handles  42  and/or  44 . In the depicted preferred embodiments, the second handle  44  is shown beneath (in the orientation shown) the first handle  42 . It will be recognized that the pivoting handle  44  may be pivotally attached at other positions relative to the first handle  42 , including above the first handle  42  or at other positions. 
   A ram or plunger  62  is slidably received within a plunger orifice  52  in the inner jaw member  36 . A mechanical linkage or coupling is provided between the second handle  44  and the plunger  62  to cause reciprocating movement of the plunger  62  in response to pivoting movement of the handle  44 . The plunger  62  moves from a retracted position within the jaw member  36  (see  FIG. 3 ) to an extended position into the jaw opening  34  and toward the outer jaw member  38  (see  FIG. 4 ) when the handle is moved from the open position to the closed position. Optionally, a latch or fastener (not shown) may be provided to retain the handles in the closed position, e.g., for more compact storage when the tool is not in use. 
   Any mechanical coupling or linkage capable of producing a reciprocating sliding movement of the plunger  62  in response to pivoting movement of the handle  44  may be employed. Referring now to  FIG. 6 , there is shown a hand tool embodiment  60  illustrating a first exemplary coupling means including a pivoting cam  54  attached to the handle  44  and which bears against the plunger  62 . A spring  56  received within a channel formed in the first handle  42  includes a first end  58  affixed therein and a second end  64  attached to the plunger  62 . When the second handle  44  is moved to the closed position, the cam  54  bears against the plunger  62  and the plunger  62  is thereby moved to the extended position against the urging of the spring  56 . When the second handle  44  is released, the spring urges the plunger  62  back to the retracted position and the handle  44  back to the open position. 
   Referring now to  FIG. 7 , there appears a hand tool embodiment  70  illustrating a second exemplary mechanical coupling means wherein a pivoting cam arm  54  attached to the handle  44  bears against an enlarged base  68  of the plunger  62 . A spring  66  is coaxially disposed about the plunger  62 . In operation, the second handle  44  is moved to the closed position and the cam  54  moves the plunger  62  to the extended position against the urging of the spring  66 . Upon release of the handle  44 , the spring  66  urges the plunger to the retracted position and the handle  44  returns to the open position. It will be recognized that the depicted mechanical linkages between the ram  62  and the pivoting handle  44  are exemplary and illustrative only and that all manner of linkages or mechanical couplings for actuating the ram  62  are contemplated, as would be understood by persons skilled in the art. 
   The manner of operation of the present hand tool can best be seen in  FIG. 6 . In operation, the tool  60  is placed about a transverse duct flange member  12  having a corner connector  20  to be connected via crimping thereto. The tool  60  is placed near the duct corner and the transverse flange portion  12  is seated against the intermediate jaw portion  40  so that the duct wall  14  is adjacent the outer jaw member  38  and the upstanding lip portion  18  is adjacent the inner jaw member  36 . When the second handle  44  is moved from the open position to the closed position, the reciprocal movement of the plunger  62  toward the outer jaw member  38  causes the upstanding lip  18  to be bent over the corner connector  20 . The handle  44  is released and the operation may be repeated one or more times at successive adjacent positions to form the desired crimped connection  26  (see  FIG. 1 ). The procedure is then repeated for each leg  24  of each corner connector  20  that is to be attached to the duct section  10 . 
   The jaw opening  34  may be sized to accommodate the transverse duct flange member  12  via a number of methods. For example, as shown in the embodiment of  FIGS. 3 and 4 , an insert  72  may be secured within the jaw opening of a rivet squeezer such as an aircraft rivet squeezer having a generally C-shaped jaw opening. The insert  72  may be secured via one or more of welding, mechanical fasteners, adhesives, or the like. The insert  72  is of a size and shape to define a generally rectangular jaw opening  34  and, upon seating a transverse duct flange member  12  within the jaw opening, to bring the upstanding lip  18  of a transverse duct flange  12  to a position relative to the plunger  62  so as to be bent over the corner connector  20  when the handle  44  is pivoted to the closed position. 
   An alternative to the jaw opening insert  72  is shown in the hand tool embodiment  50  appearing in  FIG. 5 . As shown in  FIG. 5 , a rivet squeezer with a generally C-shaped jaw opening may alternatively be modified by welding or otherwise fastening or securing a plate  74  to one or both sides of the tool head  32  at a position adjacent the jaw opening. The plate  74  is of a size and shape to define a generally rectangular jaw opening  34  and, upon seating a transverse duct flange member  12  within the jaw opening  34 , to bring the upstanding lip  18  of a transverse duct flange member  12  to a position relative to the plunger  62  so as to be bent over a corner connector  20  when the handle  44  is pivoted to the closed position. 
   In still further embodiments, as shown in connection with the tool  60  of  FIG. 6  and the tool  70  of  FIG. 7 , the inner, outer, and intermediate jaw members  34 ,  36 , and  38 , respectively, may be integrally formed of appropriate dimensions to define a generally rectangular jaw opening  34  and, upon seating of a transverse duct flange  12  within the jaw opening  34 , to bring the upstanding lip  18  of a transverse duct flange member  12  to a position relative to the plunger  62  so as to be bent over a corner connector  20  when the handle  44  is pivoted to the closed position. 
   The plunger  62  may be any of a number of geometric configurations. Preferably, the plunger  62  has a generally circular cross-sectional shape, although rectangular and other cross-sectional shapes are contemplated. In certain embodiments, the plunger  62  may have a bearing surface which is generally perpendicular to the direction of travel (see  FIGS. 4-7 ). In other embodiments, the bearing surface may be inclined with respect to the axial direction to provide increased mechanical advantage and thus ease of operation. Referring now to  FIG. 8 , there is shown a fragmentary view of an exemplary tool  80  embodiment in which the plunger  62  includes an angled or inclined planar bearing surface  82 . The angle of incline of the bearing surface  82  with respect to the axial direction of the plunger  62  is preferably in the range of from about 30-60 degrees and more preferably about 45 degrees. 
   Referring now to  FIG. 9 , there is shown a fragmentary view of an exemplary tool  90  embodiment in which the plunger  62  includes an generally conical bearing surface  92 . The angle of incline of the conical bearing surface  92  with respect to the axial direction of the plunger  62  is preferably in the range of from about 30-60 degrees and more preferably about 45 degrees. The inclined bearing surfaces shown in  FIGS. 8 and 9  are exemplary only and other tapered or inclined geometric configurations are contemplated, such as frustoconical, pyramidical, frustopyramidical, and others. 
   The invention has been described with reference to the preferred embodiments. Modifications and alterations will occur to others upon a reading and understanding of the preceding detailed description. It is intended that the invention be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.

Technology Category: 4