Patent Document

TECHNICAL FIELD 
     A punch die holds a fluid connector for forming a bead lock on the end of a cylindrical tube internal to the fluid connector thereby eliminating the need for either brazing or post process plating. 
     BACKGROUND 
     There are many applications in which a bead lock is formed at the end of a malleable cylindrical tube. Such bead locks are utilized to secure the tube to hoses or to some type of fluid device such as a hydraulic pump or valve. Such bead locked tubes are also used for securing tubes to systems carrying fluids such as fuel or brake fluids. 
     To form the bead lock on the end of a tube, it has been known to utilize a die assembly to radially deform and thereby expand the tube to form the bead lock separate from or external to the fluid connector. These die assemblies typically comprise a holder secured to the tube to prevent undesired axial movement of the tube relative to the die when the forming operation is performed. According to the prior art, the tubing holder and the forming die are moved together thereby radially expanding the tube into the forming surfaces formed on both the holder and the die separate from any type of fluid connector. The fluid connector is then joined to the longer tube by furnace brazing. In that process, the forming surface of the die would deform the surface of the bead lock axially closest to the free end of the tube while the forming surface on the tube holder would form the opposite axial end of the bead lock if one is needed. The heat applied during the brazing process causes the tube to deform slightly resulting in a misaligned assembly that must be either re-worked or discarded. 
     The disclosure of U.S. Pat. No. 6,572,358 to Blethen describes a die assembly for forming a bead lock on a cylindrical tube which includes a holder which secures the tube against axial movement so that a portion of the tube protrudes outwardly from the holder along a pre-determined axis and in which the holder has a forming surface which lies against the tube to be formed. The die assembly of the &#39;358 patent further includes a first die part having a cylindrical mandrel aligned with and engaging with the tube. In its first position, the holder abuts against the second die part while the second die part is in its extended position. Conversely, as the holder is moved to its second position relative to the first die position the holder moves the second die part to its retracted position thus radially outwardly deforming the bead lock between the forming surface in the holder and the conical surface on the sleeve. Since the through bore formed in the second die part circumscribes and constrains the tube around the bead lock during the entire formation of the bead lock, and also since the holder remains in contact with the second die part during the entire deformation process, the bead lock is not only accurately formed on the tube, but the possibility of a burr forming between the holder and the second die part is altogether eliminated. 
     Thus, it is evident that while this prior art die assembly for forming a bead lock on a cylindrical tube produces a satisfactory product, it does so while using a very complicated and expensive piece of forming equipment separate from the fluid connector. More importantly, the bead locked tube is then brazed to a longer length of tubing and all of the assembled pieces must be thoroughly cleaned prior to the brazing process. The heat applied for brazing warps the components in an unpredictable manner requiring re-work or the parts to be discarded. 
     Another well known method of forming a bead lock on a cylindrical tube is disclosed in U.S. Pat. No. 3,575,033 to Meyer. In the &#39;033 patent, a die member contains an annular passage that surrounds the exterior of a tube end and a guide pin that extends into the passage in the tube beyond the location of a desired bead lock. The tube is clamped into a holder at the approximate location of the bead lock and a force is applied to the die member to move the member toward the holder. This movement deforms the tube wall outward between the die member and the holder, thus forming a bead lock on the tube at a point remote from the tube end and separate from any type of fluid connector. This tubing bead locker does not control the outside diameter of the bead lock formed on the cylindrical tubing so that the process itself must be altered and changed to control the outside diameter of the bead lock by varying the degree that the die member is axially moved depending on the wall thickness and spring characteristics of the tube itself. Subsequently, the bead locked tube is assembled to a fluid connector and then brazed to a long tube. 
     The prior art processes includes cutting the unplated tubes to length; clean the components to prepare for brazing; form the outside diameter of the global nipple; furnace braze the joint; apply a trivalent plating to the joint; inspect for internal rust or corrosion and if required, sand blast and lube; end form the mating end per customer requirement; bend the assembly to print; and finally ship to stock. 
     SUMMARY 
     The tube punch forming die of the present disclosure holds the fluid connector and a sizing mandrel that constitutes a die assembly. Using this punch die, a bead lock is formed internal to the fluid connector where a bead lock forming groove of the fluid connector closely controls the dimensions of the bead lock that is formed in the tubing that retains and seals the tube to the connector by performing the bead lock forming process inside the connector. The tube concurrently engages the sizing mandrel which maintains the minimum inside diameter of the tube as the bead lock is formed. 
     The inside contour of the cavity in the fluid coupling is designed to hold the open end of the tube in a support ring while the tube bead lock is formed by punching the die assembly while holding the end of the tube stationary in the fluid connector and allowing the side of the tube to buckle into the bead lock forming groove when the die is activated. The bead lock is formed inside the fluid connector and thus, the fluid connector is already assembled to the tube without a brazing operation which would require cleaning, heating and subsequent plating. In the process disclosed in this application, long sections of tube can be used without deformation over its length because brazing is not used to attach a bead locked tube to a longer section of straight tube. The present disclosure is a method of forming a bead lock inside a fluid connector having a hose nipple to retain the connector on a plated tube without using brazing. 
     The new process includes the following steps: cut tubing having a trivalent coating to length; end form mating end per customer requirement; end form hose end; bend the assembly to print; ship to stock. The exemplary tube forming process is a two punch process where the first punch reduces the end diameter of the tube and can be performed on a Manchester end former. The second punch uses a punch die which holds the fluid connector and installs the nipple and creates the bead lock internally in a bead lock forming groove formed inside the connector. Since there is no brazing or welding process involved, the tube remains basically straight since it is not subjected to high levels of heat. The absence of heat results in a relatively straight tube that can be accurately bent. 
     This new process also allows for the retention of rust inhibitors or oils on the inside or on the outside of the tube to prevent corrosion. The use of brazing or welding would require that the tube be cleaned both internally and externally of all contamination if the braze or weld is going to be successful. Once the rust inhibitor or oil is removed, rust can rapidly form and is considered a contaminant which has to be removed prior to use and is especially difficult to remove once the trivalent plating is applied. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross-sectional view of the fluid conveyance tube after the end diameter of the tube has been reduced; 
         FIG. 2  is a cross-sectional view of the exemplary fluid connector and punch die and sizing mandrel; 
         FIG. 3  is a cross-sectional view of the tube just prior to insertion into the fluid connector and the sizing mandrel which are held by the punch die; 
         FIG. 4  is a cross-sectional view of the tube fully inserted into the fluid connector and into the sizing mandrel just prior to forming; and 
         FIG. 5  is a cross-sectional view of the tube with a formed bead lock inside the fluid connector and over the sizing mandrel. 
     
    
    
     DETAILED DESCRIPTION 
     Referring now to the discussion that follows and also to the drawings, illustrative approaches to the disclosed systems and methods are shown in detail. Although the drawings represent some possible approaches, the drawings are not necessarily to scale and certain features may be exaggerated, removed, or partially sectioned to better illustrate and explain the present disclosure. Further, the descriptions set forth herein are not intended to be exhaustive or otherwise limit or restrict the claims to the precise forms and configurations shown in the drawings and disclosed in the following detailed description. 
     Moreover, a number of constants may be introduced in the discussion that follows. In some cases illustrative values of the constants are provided. In other cases, no specific values are given. The values of the constants will depend on characteristics of the associated hardware and the interrelationship of such characteristics with one another as well as environmental conditions and the operational conditions associated with the disclosed system. 
     Now referring to  FIG. 1  of the drawings, a partial cross-sectional view of a fluid conveyance tube  20  is shown after an end of the tube  20  has been “necked down” to a specified diameter using a first punch forming die or other tube forming process. A Manchester tubing former machine can be used to neck down the tube  20 . The tube  20  is preferably burr free and has an oil or other rust inhibitor can be applied to its inner and outer surfaces or the surface can be plated. The tube  20  is preferably fabricated of some type of formable metal or metal alloy and can be plated with a process such as a trivalent plating. Other protection coatings or plating processes can be used when using the exemplary bead lock forming process since no high heat is applied to the tubing unlike when brazing is required. 
     Now referring to  FIG. 2  of the drawings, a cross-sectional view of a fluid connector  30  and a second punch forming die  40  and a sizing mandrel  50  are shown. These three elements make up a die assembly. The fluid connector  30  is inserted into and is temporarily held by the second punch forming die  40  during a second punch forming process to form a bead lock  24  (see  FIG. 5 ) on the tube  20 . Prior to the second punch forming process, a sizing mandrel  50  is inserted into the forming die  40  and engages the inside diameter of the fluid connector  30  to maintain a minimum inside diameter of the tube  20  when the bead lock  24  is formed by hitting the punch die  40 . 
     Now referring to  FIG. 3  of the drawings, a cross-sectional view of the exemplary punch forming die  40  holding the fluid connector  30  and the sizing mandrel  50  making a die assembly  41  just prior to insertion and forming of a tube bead lock  24  on the tube  20  is shown. For clarity, the second punch forming die  40  is not shown which holds the fluid connector  30  and the sizing mandrel  50  as the tube  20  is inserted into the fluid fitting  30  and the punch die  40  is “hit”. The internal cavity of the fluid fitting  30  is shaped to accommodate the tube  20  and hold it in position as the second punch die  40  is hit to form the bead lock  24 . Also not shown is some type of holding device for the tube  20  which must hold the tube  20  in relative position to the punch die  40  as the bead lock  24  is formed. 
     The inner cavity of the fluid connector  40  includes several individual cylindrically shaped cavities and surfaces. Lead section  32  guides the tube into the fluid connector  40  and over the sizing mandrel  50 . Bead lock forming groove  33  is shaped so that the tube  20  buckles into the bead lock forming groove  33  to form a bead lock  24  having the desired dimensions. Chamfer section  34  allows the tube  20  to transition into the cylindrical support ring  35  just prior to the bead lock forming operation. The end of the tube  20  is held in the fluid connector  30  against an inner surface  36 ′ of the end support  36  when the bead lock  24  is formed by impacting the punch die  40 . In particular, as illustrated and exemplified in  FIGS. 4 and 5 , the end of the tube  20  is held in direct contact against the inner surface  36 ′ of the end support  36  when the bead lock  24  is formed by impacting the punch die  40 . 
     Now referring to  FIG. 4  of the drawings, a cross-sectional view of the tube fully engaged in the second punch forming die  40  and over the sizing mandrel  50 . The internal diameter of the tube  20  is opened up to a specified diameter when the sizing mandrel  50  is forced inside the tube  20  as the punch forming die  40  and the fluid connector  30  are forced into the end of the tube  20 . The end of the tube  20  is shown as positioned against the end support  36  and has reached the end of its travel. Further movement of the punch forming die  40  would cause a buckling of the wall of the tube  20  into the inner cavities  32 - 36  of the fluid connector  30 . 
     Now referring to  FIG. 5  of the drawings, a cross-sectional view of the tube fully engaged with the second punch die  40  (see  FIG. 3 ) and buckled at the bead lock  24  into the inner cavities  32 - 36  of the fluid connector  30  is shown. The inner cavity of the fluid connector  40  includes several individual cylindrically shaped cavities and surfaces. Lead section  32  guides the tube into the fluid connector  40  and over the sizing mandrel  50 . Bead lock forming groove  33  is shaped so that the tube  20  buckles into the bead lock forming groove  33  to form a bead lock  24  having the desired dimensions. Chamfer section  34  allows the tube  20  to transition into the cylindrical support ring  35  just prior to the bead lock forming operation. Adjacent to the support ring  35  is an end support  36 . The end of the tube  20  is held in the fluid connector  30  at the end support  36  when the bead lock  24  is formed by impacting the punch die  40 . Upon impact of the second punch die  40 , the wall of the tube  20  is buckled outward in a cylindrical fashion to occupy the bead lock forming groove  33 . In this manner, the tube bead lock  24  has been formed while completely internalized inside the fluid connector  30  which is held in the punch forming die  40 . 
     After the bead lock  24  is formed, the mandrel  50  is withdrawn and the punch die  40  is pulled away from the fluid connector  30  and the connected tube  20 . The assembly is then ready for final bending of the tube and connection of a socket (not shown) to the socket groove  37  and then a hose (not shown) over the connector chamfer  39  and onto to the hose nipple  38 . The socket is then crimped to apply a clamping force on the hose over the hose nipple  38 . The bead lock  24  holds and seals the tube  20  to the fluid connector  30 . Since no brazing is required, the inner surface of the tube  20  can be protected against corrosion before and after all forming operations. 
     The present disclosure has been particularly shown and described with reference to the foregoing illustrations, which are merely illustrative of the best modes for carrying out the disclosure. It should be understood by those skilled in the art that various alternatives to the illustrations of the disclosure described herein may be employed in practicing the disclosure without departing from the spirit and scope of the disclosure as defined in the following claims. It is intended that the following claims define the scope of the disclosure and that the method and apparatus within the scope of these claims and their equivalents be covered thereby. This description of the disclosure should be understood to include all novel and non-obvious combinations of elements described herein, and claims may be presented in this or a later application to any novel and non-obvious combination of these elements. Moreover, the foregoing illustrations are illustrative, and no single feature or element is essential to all possible combinations that may be claimed in this or a later application.

Technology Category: 2