Abstract:
A tube coupling ( 10 ) has a tubular fitting ( 14 ) with a nipple ( 18 ) with at least one exterior annular groove ( 20 ). A deformable tube ( 12 ) has one end to fit over the nipple and has a crimp section ( 28 ) deformed into the groove with longitudinally extending ribs ( 30 ) circumferentially spared about the tube.

Description:
TECHNICAL FIELD  
       [0001]     The field of this invention relates to a crimping die machine and a crimp construction.  
       BACKGROUND OF THE DISCLOSURE  
       [0002]     Crimping die tools have long been used to produce a crimp that connects a fitting onto a hose. The crimp die tools are often complicated pieces of machinery with many moving parts and often several crimping fingers having different lengths and different shaped cam ends to complement the die tool drive mechanism. Because of the individuality of each finger, inventory for spare parts becomes burdensome.  
         [0003]     It is also known that rigid tubing used to transfer gases during the actuation of side airbags in automotive vehicles is commonly fastened to the gas supply canister via a threaded fitting on the canister connected to a nut on the tubing.  
         [0004]     What is needed is lighter weight connection between the canister and the tubing that is adapted for a single high pressure use. What is needed is a tube that is crimped onto a fitting for the canister with a structurally secure and tight crimped connection that only requires the tube and fitting to achieve the crimp and eliminate the need for fastener items, for example, ferrules, clamps, threaded fasteners, gaskets and adhesives.  
         [0005]     What is also needed a crimping apparatus that has interchangeable crimping fingers which are driven to simultaneously achieve the closed position.  
       SUMMARY OF THE DISCLOSURE  
       [0006]     In accordance with one aspect of the invention, a tube coupling has a tubular fitting with a central passage and an annular wall with at least one exterior annular groove. Preferably, the fitting has two exterior annular grooves axially spaced from each other with an exterior raised ring section interposed therebetween. A tube being made of a normally rigid but deformable under heavy loads material, for example steel, has one end with an internal diameter sized to fit over the fitting. If needed or preferred, the tube end can be swaged up or down to accommodate the fitting. The tube has a crimp section deformed to be crimped into the annular groove to also have two exterior annular grooves or crimped. The tube also has a plurality of longitudinally extending ribs spanning the crimp section circumferentially spaced about the tube. The ribs span each of the crimped sections. The ribs are formed by deformation of the tube wall by folding of the wall onto itself. The thickness of each rib is slightly less than twice the thickness of the tube material from its inner and outer diameter. Preferably in order to make an effective crimp, the amount of tube material extruded from the grooves corresponds to the amount of material used to form the ribs.  
         [0007]     In one embodiment, the exterior raised ring section is tapered toward its outer diameter with an outer diameter wall and opposing canted walls. The crimp sections have opposing walls abutting the opposing canted walls.  
         [0008]     In accordance with another aspect of the invention, a crimping machine for crimping a tube over a grooved fitting has first and second driver bases with first and second cages respectively mounted thereon. The first driver base and first cage are movable with respect to the second driver base and second cage between a closed position and an open position. At least one crimp die finger having a jaw tooth is mounted on each cage for movement between an open and closed position. Each die finger has distal wall sections that abut an adjacent finger when in the closed position. The jaw tooth ends short of the distal wall sections to form a notch such that when adjacent fingers are in a closed position, the notches provide a gap between the fingers in which the tube can be deformed.  
         [0009]     In accordance with another aspect of the invention, a crimping machine has a plurality of crimp die fingers mounted in each cage. One of the crimp die fingers in each cage is aligned along the axis of motion of the cages and moves with respect to its cage along the axis of motion. The remaining crimp die fingers have their longitudinal axis set at an angle from the axis of motion of the cage and move along their longitudinal axis i.e. canted relative to the axis of motion of the cage.  
         [0010]     The driver base is preferably movably connected to the respective mounted cage. Each driver base has a drive surface perpendicular to the axis of motion of the cage section for engaging the one aligned crimp die finger. The driver base also has canted drive surfaces angled with respect to the axis of motion of the cage section for abutting the remaining crimp die fingers. The crimp die fingers are movable in each cage as each cage moves from an open position to a closed position. The driver base is movable from its open position to its closed position to move all the crimp die fingers in the cages to achieve a closed crimping position simultaneously.  
         [0011]     In one embodiment, the respective driver base is spring loaded away from its respective cage. The crimp die fingers are also spring loaded in their cages toward the open position.  
         [0012]     In accordance with another aspect of the invention, a crimping machine for crimping a tube over a grooved fitting has first and second driver bases with first and second cages respectively mounted thereon. The first driver base and cage are movable with respect to the second driver base and cage between a closed position and an open position. Each cage has a plurality of crimp die fingers arranged circumferentially about a central axis between the two cages when in a closed position. Each crimp die finger in each cage has the same length and having a flat proximate drive end and a distal jaw end. The crimp die fingers are set at varying angles from the axis of motion of the cage. Each driver base is movably connected to its respective mounted cage. Each driver base has a plurality of drive surfaces fixed with respect to each other and flushly abut the flat proximate drive end of a respective crimp die finger. Some of these drive surfaces are angled with respect to the axis of motion of the cages for flushly abutting respective crimp die fingers. The crimp die fingers are movable in each cage as each cage moves from an open position to a closed position. The driver base is movable from its open position to its closed position to move all the crimp die fingers in the cages at rates to achieve a closed crimping position simultaneously.  
         [0013]     In accordance with another aspect of the invention, a crimp die for a crimp die machine has its jaw tooth ending short of its distal wall section such that two crimp dies are in the closed position and the distal wall sections are in abutment, a gap is formed between the jaw teeth of adjacent crimp dies.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]     Reference now is made to the accompanying drawings in which:  
         [0015]      FIG. 1  is a perspective view of a fitting with one tube crimped thereon in accordance with one embodiment of the invention;  
         [0016]      FIG. 2  is a perspective view of the fitting member shown in  FIG. 1 ;  
         [0017]      FIG. 3  is a perspective view of a fitting and tube assembly with a modified crimp connection;  
         [0018]      FIG. 4  is a fragmentary cross sectional taken along line  44  shown in  FIG. 3 ;  
         [0019]      FIG. 5  is cross sectional view taken along line  5 - 5  shown in  FIG. 1 ;  
         [0020]      FIG. 6  is a side elevational and partially schematic view of a crimp die machine for producing the crimp shown in  FIG. 1  with the bottom cage shown in an open position and the top cage shown in the closed crimping position;  
         [0021]      FIG. 7  is a view similar to  FIG. 6  showing the two cages pressed together and crimp die machine in the closed crimping position;  
         [0022]      FIG. 8  is an enlarged fragmentary side elevational view of a crimping finger shown in  FIG. 6 ;  
         [0023]      FIG. 9  is a cross sectional view taken along line  9 - 9  shown in  FIG. 8 ;  
         [0024]      FIG. 10  is a side elevational and partially schematic view of an alternate crimp die machine that produces the crimp connection shown in  FIG. 3  with the bottom cage shown in the open position and the top cage shown in the closed crimping position;  
         [0025]      FIG. 11  is an enlarged fragmentary view of the jaw ends of the crimping fingers shown in  FIG. 10  in the closed and crimping position; and  
         [0026]      FIG. 12  is a cross sectional view taken along line  12 - 12  shown in  FIG. 11 .  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0027]     Referring now to  FIGS. 1 and 2 , a metal tube  12  is crimped onto a fitting  14  to form a crimp connection  10 . The tube is made from a deformable metal, for example steel, and has a swaged enlarged end  16  sized is to fit over the fitting nipple  18 . The fitting nipple  18  has two grooves  20  therein with an annular raised ring section  22  therebetween. Each side wall  24 ,  26  of the ring section  22 , and outer walls  27 ,  29  of the grooves may have a cant of approximately 35°. It is foreseen that for most application the cant of side walls  24 ,  26 ,  27 , and  29  may range from 30° to 40°. In one embodiment, walls  24  and  27  may have a different cant than walls  26  and  29 . The fitting  14  may have two opposing nipples  18  and a body section  34  with two flange sections  38  that is connectable to a side airbag canister (not shown). Each nipple  18  has a conduit  40  which passes therethrough and fluidly communicates with a passage  42  in the body as shown in  FIG. 4 .  
         [0028]     The enlarged swaged end  16  of tube  12  has two crimp sections  28  of reduced diameter that protrude into the grooves  20  to snugly abut the outer surface of the nipple  18 . A plurality of longitudinal ribs  30  longitudinally span across each crimp section  28 .  FIG. 1  discloses an embodiment with six ribs circumferentially spaced about each crimp section  28 .  
         [0029]     As shown in  FIG. 3 , an alternative crimp connection  10  is shown with the major structural difference being that this embodiment has only two ribs  30  in each groove  20  circumferentially spaced 180° apart.  
         [0030]     Each rib  30  is formed by the wall of the tube doubled over as shown in  FIG. 4  such that a inner surface  44  of the tube abuts itself. The thickness of the rib  30  is slightly less than twice the thickness of the tube material in order to assure that the deformed metal about the rib provides for a tight abutment of the inner surface  44  with the nipple  18 .  
         [0031]     An apparatus  50  that tightly crimps the tube  12  onto the fitting  14  is shown in  FIG. 6 . The apparatus  50  has opposing cages  52  connected to the driving base  54 . Each cage  52  is provided with recesses to house three identical crimping fingers  56 ,  58 ,  60  circumferentially positioned about a central longitudinal axis  62 . Crimping finger  56  is aligned along the axis of motion  69  of the driving plate  54  while fingers  58  and  60  are at opposite canted 60° angles from the axis of motion  69  of the cage. Each finger  56 ,  58  and  60  are identically constructed with equal length and a flat proximate drive end  64  and distal jaw ends  66 . Drive end  64  of finger  56  directly and flushly abuts the drive base  54  often referred to as a base plate. The proximate drive ends  64  of fingers  58  and  60  flushly abut a canted surface  66  of a wedge  68  which is in turn securely connected to the drive base  54  and moves therewith. The direction of motion of each finger  58 ,  60  in each cage is set to be normal to the canted surface  66  and set at an angle with respect to the axis portion of  69  of the cage  52  between its closed and open position.  
         [0032]     Each finger  56 ,  58  and  60  has a lug  70  which intrudes into a recess pocket  72  in cage  52  and abuts a compression spring  74  to bias each finger radially outwardly as shown in the bottom cage  52  shown in  FIG. 6 .  
         [0033]     The drive base  54  is spring loaded via a compression spring  76  away from cage  52  when the plate  54  and connected wedges  68  are biased away, the springs  72  move the fingers  56 ,  58  and  60  radially outward as shown at the bottom cage  52  in  FIG. 6 .  
         [0034]     The drive bases  54  can be pressed together via a machine press (not shown) to move the cages  52  together until they abut each other. After the cages abut each other, further pressing of the plates  54  will overcome the compression springs  76  and move the plates  54  toward the cages  52  to drive the fingers  56  radially inward. The wedges  68  simultaneously move longitudinally with respect to the cage  52  and has its surface  66  both slide with respect to drive ends  64  and drive the canted fingers  58  and  60  radially inward. All the fingers move inwardly in a fashion to achieve a closed position simultaneously as shown in  FIG. 7 . When the fitting and tube is in position in the cages, the jaws  80  of fingers  56 ,  58 , and  60  will deform the tube  12  to form the crimp sections  28  in the grooves  20  with the ribs  30 .  
         [0035]     As shown in  FIG. 8 , the jaws  80  of each finger  56 ,  58 ,  60  has a jaw tooth  82  and sidewalls  84 . The sidewalls are constructed to abut similar sidewalls  84  of an adjacent finger when in the closed position. Jaw teeth  82  stop short of sidewall  84  to form a notch  86 . When two adjacent jaws  82  are in the closed position, two notches  86  are adjacent each other to form a gap  88  in which the metal of tube  12  is deformed therein and forms the rib  30 . The gap as shown in  FIG. 7  is slightly less than the thickness of two wall thicknesses of the tube  12 .  
         [0036]     While  FIGS. 6 and 7  disclose symmetrical and identical fingers with identical jaws  84  and jaw teeth  82  each spanning an equal arcuate portion i.e. approximately 60°, it is also foreseen that due to clearance problems where ribs  30  need to be spaced irregularly circumferentially about the tube, jaws ends may each have its jaw teeth span different angles such that the ribs can be shifted to a desired circumferential position.  
         [0037]     While fingers  58  and  60  have the same length as finger  56 , they are positioned at different angles and thus are set different initial distance fingers when in their open position from the center axis  62  as shown in  FIG. 6  so that when wedge  68  drives the jaws  58  and  60 , there is less radial movement of the fingers  58  and  60  compared to fingers  56 . However all the jaws  80  achieve the closed position and shown in  FIG. 7  simultaneously. The distance needed for driving the canted fingers  58  and  60  relative to shift rate position to finger  56  is determined by the angle of the canted surface  66  of the wedge  68  by using the cosine relative to the plane of the drive base  54 ; i.e. the distance traveled by finger  56  can be multiplied by the cosine 60°. If the wedge surface  64  is set at other angles, the cosine of the other set angle is used to determine fingers  58  and  60  distance from the closed position. This calculated distance assumes that the direction of travel of the finger  58 ,  60  in cage  52 , i.e. its radial travel is normal to the wedge surface  64 . If the direction of travel is not normal, the distance is increased depending on how far off normal the finger&#39;s direction of travel in the cage is from the wedge surface  54 . It can be foreseen that different number of fingers can be set at different angles with all the fingers achieving the closed position simultaneously.  
         [0038]     Referring now to  FIGS. 10, 11  and  12 , a modified crimping apparatus  50  is shown. Corresponding parts will have the same designated numerals for ease of comparison. In this apparatus, the same drive bases  54  can be used. Each cage  52  is constructed to house a single finger  56  that is axially aligned with the axis of motion  69  of the drive base  54 . Each finger  56  has its proximate drive end  64  abut the drive base  54 . Jaw  80  is constructed similarly as the previously described jaw with the major exception being that the span of the jaw  80  is approximately 180° minus room for the notch  86 . The distal ends  90  of each finger  56  abut each other in the closed position as shown in  FIG. 11 . The two notches  86  form gap  88  in which oppositely positioned ribs  30  are formed in the crimp connection.  
         [0039]     One advantage of having the ribs  30  extend longitudinally along the crimp  28  is increased structural strength against longitudinally directed pull forces that may want to separate the tube  12  from the fitting  14 . Two crimp sections  28  each having ribs  30  reinforcing the crimp connection  10  provides for a structurally sound and sealed connection.  
         [0040]     The crimping apparatus can be found to be advantageous. The machine uses identical fingers such that the single finger may be replaced from a common stock. Each finger&#39;s travel distance to and from the closed position is simply calculated and constructed to achieve a simultaneous closing with the other fingers.  
         [0041]     While the application of this crimp connection is described to be used for side air bag canister connections, it is easily foreseen that other applications may be suitable for this crimp connection.  
         [0042]     Variations and modifications are possible without departing from the scope and spirit of the present invention as defined by the appended claims.