Abstract:
An apparatus and method for operating a staking assembly includes a housing defining a machining passage having a longitudinal axis, an actuator rod disposed for axial movement along the longitudinal axis in the machining passage, having a first end configured to connect to a linear-reciprocating source of movement and a second end having a tool configured to deform a boss, and an air source configured to selectively provide a source of heated air.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of U.S. Provisional Patent Application No. 62/201,740, filed Aug. 6, 2015, which is incorporated herein by reference in its entirety. 
     
    
     BACKGROUND 
       [0002]    Hot air, cold stake machining uses heated air and a cold tool to deform a malleable boss or stud. A malleable boss protruding from a first component fits into a hole or space in a second component. The heated air softens the boss, increasing malleability by thermal transfer from the heated air. Once appropriately heated, a cold tool deforms the head of the plastic boss, which mechanically locks the first component and the second component together. Hot air, cold stake devices traditionally have a nozzle with an air inlet conduit to receive the heated air, and direct the heated air out an air outlet conduit to heat the boss. Air exiting the air outlet conduit generally results in turbulent airflow, increasing the time for the heated air to reach the boss by decreasing air velocity, resulting in heat loss, increased cycle time, and ultimately greater operational costs. 
       BRIEF SUMMARY OF THE INVENTION 
       [0003]    In one embodiment, a hot air, cold stake machining apparatus includes an air conduit having a heating element; a nozzle having an air conduit with a horizontal axis, and an actuator conduit having a vertical axis; the air conduit is fluidly connected to actuator conduit; and the horizontal axis of the air conduit is radially offset from the vertical axis of the actuator conduit to induce cyclonic or helical action in the air. 
         [0004]    The apparatus may additionally comprise a sensor. Sensors may include but are not limited to proximity sensors or temperature sensors. Proximity sensors may be utilized in a nozzle conduit wherein hot air flow from an air conduit may cease upon sensing proximity of a cold staking tool. Additionally, proximity to a boss may be measured via sensor. Temperature sensors may be utilized to optimize air temperature created by a heating element or to determine optimal time to cold stake a boss based upon boss temperature. 
         [0005]    In an additional embodiment, the invention relates to a method of hot air, cold staking comprising steps of: inserting a boss, attached to a first component, through a hole or aperture in a second component; directing heated air into a cold staking nozzle; further directing heated air out of a first nozzle conduit and into second nozzle conduit in an offset manner wherein the horizontal axis of the first conduit is radially offset from the vertical axis of the second conduit causing a cyclonic or helical airflow; heating said boss with heated air rendering said boss deformable; and staking said heated boss with a cold stake tool, deforming the boss to a desired orientation, wherein the deformed boss mechanically attaches the first component to the second component. 
         [0006]    The method may further comprise utilizing sensors to control or hasten operations. Steps comprising measuring airflow temperature, boss temperature, cold stake proximity, or other measurements may be contemplated. 
         [0007]    The method may further comprise forcing the airflow through a conical section with a decreasing diameter, effectively increasing air velocity and decreasing air pressure creating a venturi effect. The created venturi effect draws external air over and around a cold stake tool to maintain equilibrium pressure in the system as the heated air flows of the nozzle conduit. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    In the drawings 
           [0009]      FIG. 1  is an elevation view of a cold stake system according to an embodiment of the invention; 
           [0010]      FIGS. 2A-2C  are elevation views of the cold stake system of  FIG. 1  performing a staking process according to an embodiment of the invention; 
           [0011]      FIG. 3  is a perspective view of a cold stake nozzle according to an embodiment of the invention; 
           [0012]      FIG. 4  is a top view of the cold stake device nozzle of  FIG. 3 ; 
           [0013]      FIGS. 5A-5C  are views of the flow path and temperature profile of heated air traveling through the nozzle of  FIG. 3  according to an embodiment of the invention; 
           [0014]      FIGS. 6A-6C  are views of the flow path and temperature profile of heated air traveling through a non-offset nozzle. 
       
    
    
     DETAILED DESCRIPTION 
       [0015]    Turning now to the drawings and to  FIG. 1  in particular, there is shown an elevation view of a hot air, cold stake device to be incorporated into a machining system. The hot air, cold staking system  10  may be attached to a larger mechanical system (not shown) by mount  12 , using any standard attachment means, such as screws or bolts. The mount  12  is generally L-shaped, having a vertical arm and a horizontal arm. The horizontal arm centrally surrounds an upper end of the hot air, cold staking system  10  at the bottom of the mount  12 . The vertical arm extends upwardly, perpendicular from the horizontal arm with orifices for mounting to a larger mechanical system. In additional embodiments, the mount  12  may be of any general shape, enabling attachment of the hot air, cold staking system  10  to a larger mechanical system. 
         [0016]    Attached to and depending from the mount  12  are elements comprising an actuator system  56  including an actuator rod  16 , a drive connector  14 , a spacing element  48 , a housing  20 , a cold stake tool  34 , and upper and lower rests  38   a ,  38   b . Extending on a vertical axis through and upward from horizontal arm is the actuator rod  16 . The actuator rod  16  is of an elongated cylindrical shape extending throughout the hot air, cold staking system  10 . The top of the actuator rod  16  ends in a drive connector  14  for connection to an actuator drive (not shown). Extending downward from the horizontal arm of the mount  12  is a spacing element  48 . The spacing element  48  is cylindrical with a diameter greater than the actuator rod  16 . The spacing element  48  is hollow in the center to surround the actuator rod  16  and accommodate the reciprocating motion of the actuator system, while providing a surface for the mount  12  to attach. The spacing element  48  has a height sufficient to separate a lower portion of the hot air, cold staking system  10  from the mount  12 . Below the spacing element  48  is a conduit mount  28 . The conduit mount  28  is of an asymmetric elliptical shape, with an enlarged area on the actuator side. The asymmetric side is enlarged to create a flush outer surface with the other elements of the actuator system. 
         [0017]    Below the conduit mount  28  is the cylindrical actuator housing  20 , and the cylindrical upper and lower rests  38   a ,  38   b  above and below, respectively, the actuator housing  20 . Each rest  38   a ,  38   b  has a diameter equal to the actuator housing  20 , the spacing element  48 , and the enlarged side of the conduit mount  28 . Each rest  38   a ,  38   b  is internally hollow, to accommodate the reciprocation of the actuator rod  16 . Additionally, each rest  38   a ,  38   b  contains an air inlet  18 , which acts to prevent pressure build-up or resistance within the actuator housing  20 , maintaining mechanical efficiency of the hot air, cold staking system  10 . The actuator housing  20  is generally hollow, allowing for a reciprocating motion of the actuator rod  16  within the housing  20 . The internal diameter of the actuator housing  20  is greater than that of the spacing element  48  or rests  38   a ,  38   b  allowing for movement of an internal stop which may be appreciated in  FIGS. 2A-2C . 
         [0018]    Below the housing  20  is the cold staking nozzle  22 . The actuator housing  20 , at the bottom rest  38   b , abuts the cold staking nozzle  22 . The actuator housing  20  or bottom rest  38   b  may attach to the cold staking nozzle  22  by any standard means such as threaded connection, welding, or may just rest on top of the cold staking nozzle  22 , or any other connection means common in the industry. The cold staking nozzle  22  is described in detail in the description of  FIGS. 3 and 4 . 
         [0019]    From a top view, the cold staking nozzle  22  is shaped similar to the conduit mount  28 , in an asymmetric elliptical manner. See  FIG. 4 . The actuator housing  20  and general actuator system adjoins, connects to, or abuts the larger, asymmetric side of the cold staking nozzle  22 . At the bottom of the actuator system  56  is the cold stake tool  34 . At the bottom of the cold staking nozzle  22  is a lower aperture  24  or machining outlet. The lower aperture  24  is a hollow cylinder, which extends downwardly from the body of the cold staking nozzle  22  for directing airflow toward a deformable element and enclosing the cold stake tool  34 . Connected to the cold staking nozzle  22 , next to and parallel to the housing  20 , is the air conduit  30 . The air conduit  30  is an elongated hollow cylinder allowing internal airflow. The air conduit  30  connects at its bottom to the cold staking nozzle  22  by any common connection means including but not limited to threaded connection or welding. At the top of the air conduit  30  is a conduit inlet  26 . The conduit inlet  26  is a means for connection to a heated air source or positive pressure air source configured to selectively provide a source of heated or pressurized air. Just below the top of the air conduit  30 , the smaller side of the conduit mount  28  holds the air conduit in place, vertical and parallel to the actuator system. The described configuration situates the air conduit  30  and the actuator system on separate vertical axes, parallel to one another. See  FIG. 3 . Intermediate components are held in place by the conduit mount  28  on the top and the cold staking nozzle  22  on the bottom. 
         [0020]    Turning now to  FIGS. 2A-2C , elevation views of the hot air, cold stake device performing a staking process according to an embodiment of the invention are shown. The internal components of the hot air, cold staking system  10  are now appreciable. The housing  20  has an internal actuator stop  60 . The stop  60  ensures that an exact actuating distance between a maximum and minimum height is maintained. At each maximum or minimum height, the stop  60  will contact either the rest  38   a  at a maximum height or the rest  38   b  at a minimum height. Additionally, the air conduit  30  connects to the cold staking nozzle  22  at conduit connection  32 . 
         [0021]    Turning now to  FIG. 2A  in particular, the internal path of airflow may now be described. Heated air is forced through the conduit inlet  26  and into the hollow body of the hot air conduit  30 . Before the airflow reaches the hot air conduit  30 , it is forced through a conical air constrictor  42 . The path of airflow through the constrictor  42  starts with a larger diameter and moves toward a smaller diameter at the head of the conical shape of the constrictor  42 , increasing airflow velocity. 
         [0022]    A boss or stud  54   a , a first plate  50 , and a second plate  52  are now situated underneath the hot air, cold staking system. The first plate  50  is situated on top of the second plate  52 . The boss  54   a  protrudes from the second plate  52  through a hole in the first plate  50 , rising above the surface of the first plate  50 . The boss  54   a  is made of a thermally malleable material, like plastic or soft metals, enabling deformation of the boss after heating it to a desired temperature. The size, shape, or orientation of the boss  54   a  may be adapted in a way allowing it to be shaped into any desired configuration by the cold stake tool  34 . 
         [0023]    Turning again to  FIG. 2A  in particular, the airflow path and initial position of the hot air, cold staking system  10  may be appreciated. The actuator rod  16  is positioned at a maximum height and actuator stop  60  abuts top rest  38   a . Heated air is forced through an airflow path  40 . The hot air enters the air conduit inlet  26 , flows through the conical head  42  decreasing diameter and increasing velocity, flows through the air conduit  30  and enters the cold staking nozzle  22  at inlet  44 . Air moves through the nozzle air inlet  44  and is diverted from a generally vertical flow to a diagonal or at least a partially horizontal flow from a vertical axis, as is shown at the nozzle air conduit  36 . As shown, the diagonal or partially horizontal flow can include any angle difference relative to a vertical axis. The heated air exits the nozzle air conduit  36  through nozzle air outlet  46 . Air flows out through the nozzle air outlet  46  and enters the cylindrical lower aperture  24  in a cyclonic or helical manner, thermally heating a boss  54   a . Once a desired boss  54   a  temperature has been reached or a predetermined time has passed to heat the boss  54   a , the heated air supply will stop. 
         [0024]    Once the boss  54   a  is appropriately heated and the heated air supply has ceased, the actuator rod  16  is driven downward, as shown in  FIG. 2B  with a downward actuator motion  70   a . The cold stake tool  34  should not be heated, thus cooling the boss  54  while shaping it. Additionally, a colder temperature cold stake tool  34  reduces sticking of boss  54  material to the cold stake tool  34 . The cold stake tool  34  presses into the heated boss  54   a , deforming it into a desired shape, resulting in a particular deformed boss  54   b . Deforming the boss  54   b  creates a physical overlap of the boss  54   b  over the top surface of the first plate  50 , mechanically attaching the second plate  52  to the first plate  50 . In  FIG. 2B-2C , a hemispherical deformed boss  54   b  is shown, but different deformed boss  54   b  shapes may be contemplated in different embodiments. 
         [0025]    Finally, as shown in  FIG. 2C , the actuator rod  16  returns to an upward position by actuator motion  70   b , as shown in  FIG. 2A . The deformed boss  54   b  mechanically attaches the second plate  52  to the first plate  50 . The process is now complete and may be cyclically repeated for additional bosses  54   a  as needed. 
         [0026]    Turning now to  FIGS. 3 and 4 , the configuration of the cold staking nozzle  22  may be appreciated.  FIG. 3  shows a perspective view of the cold stake device according to an embodiment of the invention. The cold staking nozzle  22  is a single, unitary piece, connected within the hot air, cold staking system  10 . The cold staking nozzle  22  can be described as having two portions, an upper body  80  and a lower body  82 , partially separated by a recess  84 . 
         [0027]    The upper body  80  is of an asymmetric elliptical shape, similar to the conduit mount  28 , as may be appreciated by  FIG. 4 . The upper body  80  contains an attachment means  68  for connecting or mounting the hot air conduit  30  to the cold staking nozzle  22 . At the center of the attachment means  68  is the nozzle inlet  44 . The nozzle air inlet  44  is has a cylindrical shape with a diameter equal to the hot air conduit  30  and is situated on the same vertical conduit axis  76  as the hot air conduit  30  with the axis running through the center of the cylinder. 
         [0028]    Similarly, the larger, asymmetric side of the upper body  80  contains an upper aperture  66 . The upper aperture  66  is a hollow cylindrical shape with a vertical actuator axis  74  through the center of the cylinder. The vertical conduit axis  76  and the vertical actuator axis  74  are parallel to one another. The upper aperture  66  allows the actuator system  56  to mount to, connect to, or rest upon the cold staking nozzle  22 , while allowing space for the reciprocation of the actuator system  56 . 
         [0029]    As the nozzle air inlet  44  extends downwardly, further into the cold staking nozzle  22 , it diagonally departs from the vertical conduit axis  76 , becoming a nozzle air conduit  36 , extending into the lower body  82  of the cold staking nozzle  22 . The lower body  82 , from a top view, is identical to the upper body  80  in an asymmetric elliptical shape, as may be appreciated in  FIG. 4 . From a side view, the lower body  82  is generally of an arcuate orientation, initially extending vertically downward from the upper body  80 , diagonally departing from the vertical orientation in a manner and angle similar to the nozzle air conduit  36 , eventually departing from the angle of the nozzle air conduit  36  and curving into a substantially horizontal orientation. 
         [0030]    In the center of the horizontal section of the lower body  82  is the nozzle aperture  72 . The nozzle aperture  72 , at the top, has a diameter equal to the upper aperture  66  of the upper body  80  and follows the same cylindrical path. Further down into the nozzle aperture  72 , the nozzle air outlet  46  exits into the nozzle aperture  72 . At the bottom of the lower body  82 , the lower aperture  24  extends further downward, having a hollow cylindrical shape with a diameter slightly larger than the nozzle aperture  72 , facilitating optimal airflow and direction. In additional embodiments, the lower aperture  24  may be of a diameter smaller than or equal to the nozzle aperture  72 . 
         [0031]    Turning now to  FIG. 4 , in particular, the plane of the conduit axis  78  of the nozzle air conduit  36  may be appreciated. The vertical conduit axis  76  and the vertical actuator axis  74  are both parallel to the plane of the conduit axis  78  of the nozzle air conduit  36 , but while the vertical conduit axis  76  lies in the plane of the conduit axis  78 , the vertical actuator axis  74  is offset from the plane of the conduit axis  78 . In other words, the center of the nozzle aperture  72  is offset from the plane of the conduit axis  78 . The consequent offset orientation of the nozzle air outlet  46  directs airflow into the nozzle aperture  72  in a manner offset from the center of the nozzle aperture  72 . 
         [0032]    In operation, heated air is fluidly forced into the cold staking nozzle  22  at the nozzle inlet  44 . The air is diagonally diverted from a vertical direction along the nozzle air conduit  36  and exits through the nozzle air outlet  46  into the nozzle aperture  72 . Because the plane of the conduit axis  78  and the vertical actuator axis  74  are offset, the resultant airflow is in a cyclonic or downwardly helical motion as it enters the nozzle aperture  72  from the nozzle air outlet  46 , swirling around and down the inner cylindrical surface of the nozzle aperture  72 . The air continues to move downwardly and moves into the lower aperture  24 . The hollow, cylindrical orientation of the lower aperture  24  directs the heated air onto and around the boss  54   a  in a directed manner. In additional embodiments, the lower aperture  24  may substantially surround or enclose a deformable boss  54   a , as a hot air, cold staking system  10  may be situated close to the first plate  50 , second plate  52 , and the boss  54 . 
         [0033]    In a preferred embodiment, the angle of the nozzle air conduit  36  departing from the vertical conduit axis  76  will be an angle such that optimal cyclonic or helical airflow is achieved, maximizing the amount of heat transferred to a boss  54  while minimizing heat loss and time required to heat the boss  54 . 
         [0034]    Furthermore, a means for cooling the cold stake tool  34  results from the inventive configuration of the nozzle  22 . Referring again to  FIG. 2A , the hot air is forced through a conical constrictor  42 . As the air is forced through the constrictor  42 , the system utilizes the venturi effect. As the air is forced through a decreasing diameter, the air velocity necessarily increases and static pressure decreases to maintain conservation of energy. Referring now to  FIG. 3 , as air exits the nozzle air conduit  36  into the nozzle aperture  72 , the decreased pressure of the heated air draws outside air into the recess  84  between the upper body  80  and lower body  82  of the cold staking nozzle  22  to maintain consistent pressure of the system. As the air draws into the recess  84 , the air flows over and around the cold stake tool  34 , effectively cooling the cold stake tool  34 , which may otherwise begin to warm from the radiant heat caused by the hot air environment or through thermal transfer from a heated boss  54 . 
         [0035]    Turning now to  FIGS. 5A-5C , views of the airflow path and temperature profiles of heated air traveling through the cold staking nozzle  22  of  FIG. 3  according to an embodiment of the invention are shown.  FIG. 5A  shows a perspective view,  FIG. 5B  shows a side view, and  FIG. 5C  shows a top view of the cold staking nozzle  22 . As may be appreciated, airflow velocity is represented by motion lines defined in key  90 . A solid line represents the highest velocity, a dot-dash mixed line represents a high air velocity, a dashed line represents a slower air velocity, and a dotted line represents the slowest velocity. As may be appreciated in  FIGS. 5A-5C , as airflow moves through the cold stake nozzle  22 , air velocity decreases. In a preferred environment, maximum air velocity is desirable. Maximum air velocity decreases time for heated air to reach a deformable boss  54 . By decreasing time for hot air to reach a deformable boss  54 , time required to heat the boss  54  to a desired temperature will decrease, thus increasing efficiency, decreasing operating time, and minimizing costs associated with operations. A cyclonic or helical airflow path achieves a higher airflow velocity and a preferred method of operation. 
         [0036]    Turning to  FIG. 5C  in particular, the cyclonic airflow of the system may be appreciated. The offset airflow from the nozzle air conduit  36  into the nozzle aperture  72  creates a cyclonic airflow within the nozzle aperture  72 . Furthermore, the downward orientation of the nozzle air conduit  36  combined with the offset horizontal conduit axis  78 , directs air into the nozzle aperture  72  in a downward helical motion. This helical airflow motion maintains a higher airflow velocity, achieving a more desirable environment than has previously been possible. 
         [0037]    Turning now to  FIGS. 6A-6C , a comparison with prior art non-offset air conduits may be appreciated. In  FIGS. 6A-6C , heated air is directed from a nozzle air conduit  36  into the nozzle aperture  72  in a manner where the horizontal conduit axis  78  is not offset from the vertical actuator axis  74 . Airflow does not move in a cyclonic or helical manner. 
         [0038]    Again, lines representing air velocity are shown. A solid line represents the highest velocity, a dot-dash mixed line represents a high air velocity, a dashed line represents a slower air velocity, and a dotted line represents the slowest velocity as seen in the key  90 . Turning now to  FIG. 6C  in particular, the departure from a desirable environment as seen in  FIG. 5C  may be appreciated. The horizontal axis of the nozzle air conduit is no longer offset from the vertical axes of the system. The air moving into the nozzle aperture  72  is no longer a cyclonic or helical motion, but flows directly into the opposite wall of the nozzle aperture  72 . The airflow of  FIG. 6C  is chaotic, having a greater turbulence than a cyclonic or helical system. Greater airflow turbulence results in decreased airflow velocity. The increased turbulence of the airflow increases time in which air reaches the deformable boss  54 . Increased time to reach the boss  54  results in increased time to heat the boss  54  and increases system cycle time. The hot air, cold staking process takes longer to complete and is less efficient, increasing operational costs. Furthermore, a turbulent airflow will results in greater heat transfer to a cold stake tool  34 , creating additional problems with sticking or time required to cool a boss  54  to a desired formation. 
         [0039]    Therefore, a cyclonic or helical airflow is advantageous, increasing airflow velocity, increasing heat transfer to a boss, increasing operational speed, and decreasing operational costs. Furthermore, the incorporation of a venturi effect into the system maintains a cold temperature cold staking tool  34 . A cold temperature cold stake tool  34  will enable a heated, malleable boss  54  to cool faster, further increasing operational speed and reducing sticking of the boss  54  substance to the cold stake tool  34 . 
         [0040]    In an additional embodiment, the cold staking nozzle  22  may contain a proximity sensor. The proximity sensor may be located around the nozzle aperture  72 , the lower aperture  24 , or upper body. In a first embodiment, a proximity sensor may be advantageous in determining relative closeness to a boss  54 . In another embodiment, a proximity sensor within the nozzle aperture  72  may determine a reciprocating motion from a cold stake tool  34 , stopping heated airflow and preventing unwanted thermal transfer to the cold stake tool  34 . 
         [0041]    In another embodiment, the cold staking nozzle  22  may be equipped with a temperature sensor. In a first embodiment, the temperature sensor may be situated toward the bottom of the cold staking nozzle  22 , sensing when a boss  54  has reached a desired temperature and may be cold staked. In a second embodiment, the temperature sensor may measure the temperature of the heated air entering the cold staking nozzle  22 . This may be advantageous in determining the appropriate time required to heat a boss  54  based upon air temperature and boss  54  material. Additionally, this may allow for greater user control in determining air temperature. 
         [0042]    While the invention has been specifically described in connection with certain specific embodiments thereof, it is to be understood that this is by way of illustration and not of limitation. Reasonable variation and modification are possible with the scope of the foregoing disclosure and drawings without departing from the spirit of the invention which, is defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise.