Abstract:
A fastener forming apparatus produces a fastener of metal having a rod-to-plate connection often found in such applications as an automotive door latch striker. The fastener is formed and assembled in a single operation and with only a rod and a stamped plate for parts. The forming apparatus has a die structure for securing the rod, a base for vertically aligning the rod, a compression pedestal for vertically aligning the plate and a suspended stamping structure. The stamping structure moves from a pre-staged position for loading of the rod and plate to the die structure, to an intermediate position wherein a head is substantially formed unitarily at the end portion of the rod on one side of the plate, and formation of a unitary protrusion is initiated from the same end portion but on an opposite side of the plate. The structure then moves to a formed position completing the formation of the protrusion, clamping the plate between the head and protrusion, and thus firmly attaching the plate to the rod producing the fastener.

Description:
REFERENCE TO RELATED APPLICATION 
   This application is a division of and claims the benefit of application Ser. No. 10/850,028, filed May 20, 2004, on which U.S. Pat. No. 7,159,289 issued on Jan. 9, 2007. 

   FIELD OF THE INVENTION 
   The present invention relates generally to a fastener forming apparatus for making a fastener of metal, and more particularly to an anchor or striker and a method for making it. 
   BACKGROUND OF THE INVENTION 
   Some prior fasteners of metal have a metal rod projecting from and attached to a separate metal base plate by complementary threads, a threaded nut, or a weldment. Such a fastener can be used as a striker for a vehicle door latch, or a shoulder anchor for a vehicle seat belt. Examples of door latch strikers are taught in U.S. Pat. Nos. 6,273,480 and 6,267,421 and examples of anchors for shoulder seat belts and mounting bolt structures for brake actuators are taught in U.S. Pat. Nos. 5,779,270 and 5,787,794, respectively, and incorporated herein by reference. Typically, the stamped plate is mounted to the chassis of the vehicle and the pre-mounted rod, threaded lug or striker projects therefrom to serve a particular attachment, connector or retainer function. 
   In all of these applications, the plate-to-rod connection or fastener must be reliable and capable of withstanding considerable load and without fracture. To meet these requirements, the anchor has typically been manufactured from numerous parts with numerous manufacturing and assembly steps which contribute to the overall cost of the anchor. For instance, known methods of securing a rod to a stamped plate include first forming threads on a base end of the rod, placing the base end through an aperture in the plate and then threading a nut onto the threaded base end. Another method includes manufacturing a striker sleeve having inner threads, then threading a bolt into the sleeve from the opposite or inward side of the plate. Other methods include butt welding the rod to the plate, and another method includes press fitting separate collars over the rod, inserting the rod through an aperture in the plate to bear on the collars, and then welding or causing plastic deformation of the end of the rod to engage the opposite side of the plate. 
   Strikers of door, hood and trunk latches in automotive vehicles are typically secured to the body via the stamped base plate which has a hole at each end for receiving a pair of threaded bolts which thread into the vehicle body. Often, the holes are elongated to permit some positioning adjustment of the projecting rod with respect to the body. The base plate of the striker typically has two apertures positioned between the two bolt mounting holes for receiving end portions of the rod which is generally U-shaped. Securing the rod to the base plate is not a one step manufacturing process and often requires additional parts. For instance, prior to inserting the ends of the U-shaped rod through the apertures in the base plate, separate collars are press fitted to each end or formed unitarily onto each end portion via some additional step of stamping. Once the collars are press fitted, or stamped, only then is the plate fitted to the U-shaped rod and appropriately located or seated via the press fitted or formed collars. After the base plate and the U-shaped rod with the formed collars are pre-assembled, they are attached together by welding or by two additional collars or buttons formed on the opposite side of the base plate by hot upsetting in a welder, staking in a press, or by an orbital riveting or staking process. 
   Manufacturing and assembly of the first two collars requires additional steps in the manufacturing process which contributes to the overall cost of the striker or latch catch. Moreover, the strength of the striker is dependent upon the questionable reliability of the weld, or can be influenced negatively by internal stresses created during press fitting, upsetting and staking processes. Yet further, collars formed in secondary operations have a problem with dimensions on collars to be unequal in length or thickness causing location to the stamping to vary. When the finished assembly requires parts to be over molded with plastic or insert molded the problem is magnified. 
   SUMMARY OF THE INVENTION 
   A fastener forming apparatus produces a fastener of metal having a rod-to-plate connection often found in such applications as an automotive door latch striker. The fastener is manufactured in a single operation and with only a rod and a stamped plate for parts. The forming apparatus has a die structure for securing the rod, a base for vertically aligning the rod, a compression pedestal for vertically aligning the plate and a suspended stamping structure. The stamping structure moves from a pre-staged position for loading of the rod and plate to the die structure, to an intermediate position wherein buttons are substantially formed unitarily at the end portion(s) of the rod on one side of the plate, and collars are substantially formed unitarily at the end portion(s) and on the opposite side of the plate. The structure then moves to a stamped position wherein the collar formation to the end portions is completed, thus engaging the plate to the rod between the radially projecting rod head and collar. 
   Preferably, the stamping structure has an electrode which makes initial contact with the end portion when the stamping structure moves from the pre-staged position and into an initializing position and before movement to the intermediate position. When the structure moves from the intermediate position the distance between the electrode and the plate remains constant while the pedestals compress thus reducing the distance between the plate and the die structure to complete formation of the collar without further compressing and thus sacrificing the strength of the head. 
   Objects, features and advantages of this invention include the manufacturing of a high strength and inexpensive fastener of metal such as that required for strikers of automotive door latches, and an article or striker produced from a minimal number of parts, a minimal number of manufacturing and assembly steps, and without the expense of welding. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other objects, features and advantages of this invention will be apparent from the following detailed description of the preferred embodiment and best mode, appended claims, and accompanying drawings in which: 
       FIG. 1  is a top view of a fastener forming apparatus according to one embodiment of the present invention illustrated in a loading position and with an overhead stamping structure removed to show detail below; 
       FIG. 2  is a cross section of the fastener forming apparatus taken along line  2 - 2  of  FIG. 1 ; 
       FIG. 3  is a cross section of the fastener forming apparatus illustrated in a staged position and taken along line  3 - 3  of  FIG. 1 ; 
       FIG. 4  is a cross section of the fastener forming apparatus illustrated in an initializing position; 
       FIG. 5  is a cross section of the fastener forming apparatus illustrated in an intermediate position; 
       FIG. 6  is a cross section of the fastener forming apparatus illustrated in a final stamped position; 
       FIG. 7  is a cross section of a fastener of metal according to one aspect of the present invention and produced by the fastener forming apparatus; and 
       FIG. 8  is a perspective view of the fastener of metal. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring in more detail to the drawings,  FIGS. 1-6  illustrate a fastener forming apparatus  10  of the present invention which makes a fastener of metal  12 , as best illustrated in  FIGS. 7-8  and also embodying the present invention. Preferably, the fastener of metal  12  takes the form of a striker for a door, hood, or trunk of an automotive vehicle. The striker  12  has a generally U-shaped metal rod or wire form  14  having a mid portion or bight  50  and a pair of vertical legs  42 ,  44  each having distal end portions  16 ,  18  permanently attached to a metal base plate  20  preferably having a pair of mounting through holes  22  adjacent to its ends. Each end portion  16 ,  18  of the rod extends through an aperture  23  in the plate  20  (as best shown in  FIG. 7 ) and is permanently attached to the plate by entrapment of the plate between a protrusion or collar  24  and a head or button  26 , both formed as a unitary part of its associated end portion  16 ,  18  of respective legs  42 ,  44 . 
   Preferably, the base plate  20  is made by the method of die stamping a metal base plate  20  and punching the holes  22  and apertures  23  therein. So that the plate  20  can rest flush on a mounting surface such as a vehicle body or jamb, a depression  28  is preferably stamped into the plate  20  to accommodate the axial depth of each head  26 . A preform of the generally U-shaped rod  14  is made by a wire or rod bending or stamping process. Preferably, the U-shaped rod  14  is attached to the plate  20  by inserting the free distal end portions  16 ,  18  of legs  42 ,  44  through the apertures  23  in the plate and then substantially simultaneously forming the protrusion  24  and head  26  on each leg. Preferably, all of the protrusions and heads on both legs are substantially simultaneously formed preferably by hot forming or upsetting although for some applications, they may be cold formed or upset. 
     FIGS. 1-6  illustrate the fastener forming apparatus  10  for attaching the rod preform to the mounting plate  20  by substantially simultaneously hot forming the protrusions  24  and heads  26  on both end portions  16 ,  18  of the preform with the plate  20  captured between them. The fastener forming apparatus  10  generally has a die structure  30  positioned below a suspended stamping structure  32  and between a pair of plate carriers or compression pedestals  34 . The die structure  30  and compression pedestals  34  are supported by a base  36 , which also supports a clamping device  38  (as best shown in  FIGS. 2 and 3 ) for insertion and securing the U-shaped rod  14  to the die structure  30 . 
   Referring to  FIGS. 1-2 , the forming apparatus  10  has a pre-staged or loading position  40  for placing each leg  42 ,  44  of the U-shaped rod  14  into respective generally vertical channels  46 ,  48  of the die structure  30  so that the distal end portions  16 ,  18  of each leg  42 ,  44  generally project upward from the die structure  30  and toward the suspended stamping structure  32  (not illustrated in  FIG. 2 ). The bight or generally horizontal portion  50  of the U-shaped rod  14  which extends between the two legs  42 ,  44  contacts an upward facing alignment face  52  generally carried by the base  36  for vertically aligning the end portions  16 ,  18  with respect to the stamping structure  32  and compression pedestals  34 . 
   The die structure  30  is generally divided into a first section  54  engaged rigidly to the base  36  and a second section  56  engaged to the clamping device  38 . When the forming apparatus  10  is in the pre-staged position  40 , the second section  56  is spaced horizontally away from the first section  54  thus providing a clearance  58  to insert the U-shaped rod  14 . Each section  54 ,  56  carries opposing die sides  60  which define respective longitudinal halves  62  of both channels  46 ,  48 . Once the legs  42 ,  44  of the rod  14  are positioned in the channel halves  62  of the first section  54  and the mid portion  50  is rested upon the alignment face  52 , the clamping device  38  can be closed snugly securing the rod  14  within the die structure  30  and thus positioning the forming apparatus  10  into a staged position  64 , as best illustrated in  FIG. 3 . 
   With the forming apparatus  10  in the staged position  64 , the distal end portions  16 ,  18  of each leg  42 ,  44  project upward through respective protrusion forming recesses  66 ,  68  of each channel  46 ,  48 . The recesses  66 ,  68  are defined by an annular bottom surface  70  and a substantially circular and continuous wall  72  which further defines the outer perimeter of the bottom surface  70  and extends axially upward to a top surface  74  carried by both sections of the die structure  30 . The outer radius of the recess  66 ,  68  is appreciably larger than the radius of the non-deformed rod  14  to accommodate hot forming of the protrusions  24 . 
   Also, when the forming apparatus  10  is in the staged position  64 , the compression pedestals  34  are biased yieldably upward in an extended state  76  by a coiled compression spring  102 , and project vertically beyond the top surface  74  of the die structure  30 . Each compression pedestal  34  includes a guide housing  104  that has a through bore  112  and a counterbore  108 , and an inverted piston assembly  106 . The piston assembly includes a piston rod  110  received for guided reciprocation through the bore  112  and an enlarged head  107  received in the counterbore  108 . Preferably, the extended position  76  of the piston rod  110  generally is defined by engagement of the head  107  with a radially inward projecting shoulder of the housing  104  and which in-part defines the counterbore  108 . Also preferably, the spring  102  is co-located in the counterbore  108  with the piston assembly  106  and is substantially received in a blind bore  111  in the piston assembly  106 . 
   Because a bottom side  78  of the plate  20  rests upon an end or top face  80  of the piston rod  110 , the plate  20  is generally spaced vertically above the top surface  74  of the die structure  30 . However, the distal end portions  16 ,  18  of each leg  42 ,  44  project sufficiently above the top surface  74  to extend through respective apertures  23  (see  FIG. 7 ) in the plate  20  and substantially centered in depressions  28 . Moreover, the end portions  16 ,  18  project above an opposite top side  84  of the plate  20  toward, but still spaced vertically from, the stamping structure  32 . 
   Referring to  FIG. 4 , during manufacturing, the stamping structure  32  moves downward into a contact or initializing position  86  whereupon a pair of electrodes  88  projecting downward from a support member  90 , contact the respective distal ends  16 ,  18  of the rod  14 . At this point, the inverted piston assemblies  106  of the compression pedestals  34  remain in the extended state  76 , hence the space  92  between the bottom side  78  of the plate  20  and the top surface  74  of the die structure  30  is not yet reduced. Also projecting downward toward each compression pedestal  34  and from the support member  90  are respective contact blocks  94  which remain spaced vertically from the top side  84  of the plate  20  when the forming apparatus  10  is in the initializing position  86 . 
   Once contact is made between the electrodes  88  and respective end portions  16 ,  18 , an electric current is delivered through the electrodes into the end portions  16 ,  18  of the rod  14  to heat the end portions of the legs  42 ,  44  to a hot forming temperature, thus assisting in the formation of the unitary button or head  26  and the simultaneously formation of the lower collar or protrusion  24  with the plate  20  disposed firmly in-between.  FIG. 5  illustrates this as an initial forming or intermediate position  96  of the forming apparatus  10 . When in the intermediate position  96 , the heads  26  and protrusions  24  begin forming with the downward stamping action/force of the stamping structure  32 . The contact blocks  94  make initial contact with the top side  84  of the plate  20  above the compression pedestals  34  which still substantially remain in the yieldably biased extended state  76 , and the space  92  located between the bottom side  78  of the plate  20  and the top surface  74  of the die structure  30  is not yet substantially reduced. 
   Referring to  FIG. 6 , the continued downward movement of the stamping structure  32  moves the forming apparatus  10  from the intermediate position  96  and into the final stamped or formed position  98 , this continued movement causes the piston assemblies  106  of the compression pedestals  34  to move downward into a retracted or compressed state  100  and the distal end portions  16 ,  18  to continue to flatten out causing the necessary plastic deformation to create the head  26  which contacts the top side  84  and the radially projecting unitary protrusion  24  formed in the respective recesses  66 ,  68  and contacting the bottom side  78  of the plate  20 . The forming apparatus  10  is in the formed position  98  and the striker  12  is fully formed and assembled when the bottom side  78  of the plate  20  contacts the top surface  74  of the die structure  30  as the compression pedestals  34  are driven to their retracted position by the stamping structure  32 . 
   When the forming apparatus is in the intermediate position  96 , the heads  26  are substantially formed while the space  92  is still substantially present and the protrusions  24  are partially formed. With continued downward movement of the stamping structure  32 , the heads  26 , which are most prone to deformation because they are closest to the electrodes  88 , are prevented from deforming further because contact block  94  engages the top side  84  of the plate  20 . Thus, further downward movement moves the plate  20  in unison with the electrodes  88 , and the compression pedestals  34  are forced to move from their extended state  76  to their retracted or compressed state  100  while completing the formation of the protrusions  24 . 
   Unwanted distortion of the protrusions  24  is prevented by the confines of the recesses  66 ,  68 . Similarly, the shape of the legs  42 ,  44  is maintained during the forming process by the confines of the channel halves  62  and clamping action of the first and second sections  54 ,  56  of the clamping device  38 . 
   Preferably, the rod or wire form  14  may vary in design and shape and in one presently preferred construction has a nominal diameter before forming in the range of 6 to 10 millimeters. The forming process itself with use of the electrodes  88  is a type of hot forming or upsetting which upon cooling provides stress relief and shrinks to provide a tighter interference fit between the rod  14  and plate  20 . If a tight interference fit via shrinkage is not required, the forming process need not utilize the electrodes  88  and a cold forming process can be used to create the heads  26  and protrusions  24 . 
   While the forms of the invention herein disclosed constitute a presently preferred embodiment, many others are possible. For instance, the rod  14  may not be U-shaped and instead can be limited to a single linear leg  14  engaged to a plate by a single protrusion and head. With this fastener, the clamping device  38  of the forming apparatus  10  is not required. It is not intended herein to mention all the possible equivalent forms or ramifications of the invention. It is understood that terms used herein are merely descriptive, rather than limiting, and that various changes may be made without departing from the spirit or scope of the invention as defined by the following claims.