Abstract:
A method for fixation of a jack to a panel or bracket of an electronics module. A jack having an encircling flange is machined to include a barrel having at least one longitudinal knurl and an inwardly-tapered interior section. A swaging tool includes a body having a lower surface with an open circular channel arranged to circumscribe the circular open end of the barrel of the jack. The jack is fixed to a circular port within the panel by inserting the jack into the port so that the flange contacts a surface of the panel and then applying a downward-acting force onto the swaging tool aligned with open end of the barrel to compressively fix the jack to the panel.

Description:
REFERENCE TO RELATED APPLICATION 
       [0001]    The present application claims priority from Provisional Patent Application Ser. No. 60/926,844 of inventor Joel G. Bump covering “Jack and Method For Fixation of Jack to Panel” filed in the United States Patent and Trademark Office on Apr. 30, 2007. 
     
    
     BACKGROUND 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to jacks and methods of fixation of jacks to the panels of electronics chassis. More particularly, this invention pertains to a jack suitable and to the method of swaging the jack to the panel. 
         [0004]    2. Description of the Prior Art 
         [0005]    Phono jacks are commonly used in consumer audio, video and digital devices for both the input and output of signals to a modular array of electronic elements. Such an array of elements is commonly contained within a frame comprising a number of boundary panels. 
         [0006]    The jacks are installed directly to the metal front or rear panels of finished products or to internal metal brackets, panels or circuit boards that permit the jack to protrude through the (metal or plastic) outer shell or panel of the finished product. The jack is routinely fixed by swaging it to the panel or bracket. 
         [0007]    Prior art swaging operations roll the barrel of the jack over until it contacts the backside of the panel or bracket. As a result, pressure applied by the rolled edge and by slight expansion of the smooth metal barrel of the jack provide the only forces to keep the jack secured to the panel. The smoothness of the wall of the barrel of the jack, contacting the smooth inner diameter of the port that has been drilled or punched in the panel, leave the jack subject to possible eventual rotation with respect to the panel. 
         [0008]    During normal use, a male connector is pushed into the jack and seated therein with rotating action. As the outer shell of the connector applies pressure to the perimeter of the panel-mounted jack body, such rotational action may compromise the holding integrity of the jack. Users often additionally apply angular force to the connector to help insert or easily remove it. This places additional mechanical stress on swage integrity. 
         [0009]    The rolling swage fixation process requires that a very thin gauge metal be employed for the barrel of the jack. Such thin gauge metal acts to weaken the jack in the face of the pressures applied to it by connector insertion and removal. Repetitive use often results in rotation of the jack with respect to the port in the panel. Such rotation may cause the attachment of the jack to the panel to loosen and, in some cases, fail. 
         [0010]    Loosening of the attachment of jack to panel can degrade operation of the electronic device as the mechanical contact between jack body and panel provides the ground connection for signals. A loose connection between jack body and panel will cause the signal transmitted through the jack to become intermittent and result in electrical failure of the jack. As the jack becomes loose, the center conductor is mechanically stressed and may also fail. 
         [0011]    Prior art jacks are also known having barrels with threaded outer walls for insertion into an interiorly-threaded port of a panel. The threaded barrel mounts through the thickness of the panel and is secured by a nut. Although generally more robust than jacks utilized in a roll swaging process, their installation is time-consuming. While threaded jacks are able to withstand damage from lateral or angular forces, they are subject to eventual loosening through repetitive use and vibration. 
       SUMMARY OF THE INVENTION 
       [0012]    The present invention addresses the preceding and other shortcomings of the prior art by providing, in a first aspect, a method for securing a jack to a panel of an electronics chassis. Such method is begun by machining a block of metal to provide a jack of the type that includes a barrel having an encircling flange, at least one longitudinal knurl and an inwardly-tapered interior section. 
         [0013]    A swaging tool is also provided. Such tool includes a body having a lower surface. An open circular channel is formed in the lower surface. The circular channel includes a pair of spaced-apart planar walls and a planar roof. The inner wall is of lesser diameter and the outer wall is of greater diameter than the diameter of the open end of the barrel of the jack. 
         [0014]    The jack is inserted into a circular port in the panel so that the flange contacts a surface of the panel throughout and the barrel extends beyond the opposed surface of the panel. The swaging tool is then aligned with the end of the jack so that the end of the barrel is circumscribed by the open circular channel of the swaging tool. A force is applied to the swaging tool so that the lower surface of the tool is directed to contact the open end of the jack and to exert a compressive force upon the barrel of the jack. 
         [0015]    In a second aspect, the invention provides a jack. Such jack includes a barrel having an encircling flange, at least one longitudinal knurl and an inwardly-tapered interior section. 
         [0016]    In a third aspect, the invention provides a swaging tool. Such tool includes a body having a lower surface. An open circular channel is formed in the lower surface. The circular channel includes a pair of spaced-apart planar walls and a planar roof. 
         [0017]    The preceding and other features of the invention are described in a detailed description that follows. Such description is accompanied by a set of drawing figures. Numerals of the drawing figures, corresponding to those of the written description, point to the features of the invention. Like numerals refer to like features throughout both the written description and the drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]      FIG. 1  is a side elevation view of a jack in accordance with an embodiment of the invention; 
           [0019]      FIGS. 2(   a ) and  2 ( b ) are a cross-sectional view of the jack taken at line  2 ( a )- 2 ( a ) of  FIG. 1  and an enlarged detail view taken at line  2 ( b )- 2 ( b ) of FIG.  2 ( a ) respectively; 
           [0020]      FIGS. 3(   a ) through  3 ( c ) are side elevation, cross-sectional (taken at line  3 ( b )- 3 ( b ) of  FIG. 3(   a )) and bottom plan views, respectively, of components of a swaging tool in accordance with an embodiment of the invention; 
           [0021]      FIG. 4  is a side elevation view of a swaging tool with jack arranged therein for fixation to a panel of an electronic module in accordance with an embodiment of the invention; and 
           [0022]      FIGS. 5(   a ) and  5 ( b ) are a series of enlarged cross-sectional views for illustrating the swaging of a jack to a panel in accordance with an embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0023]      FIG. 1  is a side elevation view of a jack  10  in accordance with an embodiment of the invention. The jack  10  comprises a generally-cylindrical outer shell  12  that houses a protruding pin  14 . The outer shell  12  is preferably machined from a metal rod to offer a number of significant functional features (discussed below) that cannot be achieved with a jack having a barrel formed of sheet metal. 
         [0024]    An axial groove  16  is provided for stiffening the elongated pin  14  to resist bending upon insertion into a mating plug of an electronic component (not shown). The shell  12 , which provides coaxial shielding of an electrical connection affected by means of the jack  10 , includes an encircling flange  18  and a barrel  20 . As can be seen, the barrel  20  comprises a plurality of longitudinal knurls  22 . Such knurls  22  enhance the resistance of the jack  10 , when fixed to a panel or the like, to rotational forces that would otherwise erode the grounding quality. The presence of the knurling causes the otherwise-smooth periphery of an insertion port of a panel to deform under press-fit insertion pressure, thereby acquiring a complementary texture consisting of minute alternating peaks and depressions. The knurled exterior of the barrel  20  thereafter interlocks with the above-described texture to form a bond that is highly resistant to rotational force. 
         [0025]    Other features of the jack  10  are made apparent in  FIG. 2(   a ), a cross-sectional view of the jack  10  taken at line  2 ( a )- 2 ( a ) of  FIG. 1 . The metallic pin  14  is formed integrally with a metallic base sheet  24  that is rolled into a tube for insertion within a generally-tubular molded interior  26 , preferably comprising an electrical insulator such as NYLON®, of the jack  10 . An aperture  28  at the bottom of the shell  12  is aligned with the axis of symmetry  30  of the open tubular interior  26  of the jack  10 . The aperture  28  permits the jack  10  to function, when inserted into a panel of an electrical module, as a conductor of electricity between a plug end  32  and the pin  14 . The plug end  32  provides the female element and the pin  14  the male element for making electrical connection through the jack  10 . For example, the plug end  32  may receive a plug or pin at the terminus of a wire, as the pin  14  is received by the female element of a circuit board. 
         [0026]    As mentioned above, the shell  12  is preferably machined from a rod of, e.g., number  360  half hard free cutting brass bar stock, permitting the shell  12 , including the barrel  20 , to be formed to a specific shape for enabling a swaging process that cannot be achieved by means of jacks of conventional shape and fabrication. The detailed shape of the barrel  20  will be seen to provide a design that will resist fracture during the swaging process described below. As illustrated in  FIGS. 2(   a ) and  2 ( b ), an edge  33  of the flange  18  is offset by an amount  34  from an annular edge  36  of the barrel  20 . The offset amount  34  will be seen to provide metal that is drawn into the barrel  20  to prevent the barrel  20  from fracturing as a result of the swaging process. The inventor has found that a slight outward tapering of the inner wall  37  of the barrel  20  is required to prevent it from swelling inwardly during swaging as described below. The taper additionally permits the removal of a swaging tool, described below, from the jack  10  after swaging. 
         [0027]    The swaging operation will be seen to cause the barrel  20  to flare outwardly. The inventor has found that the angle of flaring should be limited to approximately one half the value of an angle  34 ′, illustrated in  FIG. 2(   b ), that is subtended by the outer wall  38  of the barrel  20  (which is parallel to the axis of symmetry  30  before swaging) and an imaginary line  39  adjoining the points of contact of the outer wall  38  with the edge  33  of the flange  18  and the annular edge  36  with the inner wall  37  of the barrel  20  respectively to prevent fracture of the jack  10  upon swaging to a mounting panel. The inventor has further found that the value of the offset angle  34 ′ is preferably approximately eighteen degrees while the outer wall  38  of the barrel  20  should flare outwardly by no greater than 5 degrees when the barrel  20  achieves first contact with a mounting port of a panel and no greater than 9.2 degrees upon completion of the swaging operation (discussed and illustrated below). 
         [0028]      FIGS. 3(   a ) through  3 ( c ) are side elevation, cross-sectional (taken at line  3 ( b )- 3 ( b ) of  FIG. 3(   a )) and bottom plan views, respectively, of components of a swaging tool  48  in accordance with an embodiment of the invention. The tool  48  is mounted when in use in an Arbor press. Arbor presses are well known in the art, employing various technologies (e.g. rack, cam, servo, hydraulic, etc.) to apply the linear force required for swaging operations. While the method of the invention is not limited to Arbor presses, a representative hydraulically-powered Arbor press for use in the invention is commercially available from Haeger, Incorporated of Oakdale, Calif. Such a press, with tool  48 , permits the barrel  20  of the jack  10  to the guided in accordance with the invention at the same time that a measured amount of pressure is applied for its fixation to a panel. Such a fixation process will be described with reference to subsequent drawing figures. 
         [0029]    Viewing  FIGS. 3(   a ) and  3 ( b ) in combination, it is seen that the tool  48  comprises two parts, a first swaging tool member or base  50  for receiving the plug end of the jack  10  and a second swaging tool member or hammer  52  for receiving the pin end of the jack  10 . In use, the hammer  52  is actuated by the Arbor Press to apply downward pressure controllably to fix the jack  10  to a panel. 
         [0030]    The base  50  of the tool  48  includes a hollowed upper end defining a cup-like cavity  54  for receiving and positioning the plug end of the jack  10 . Such cavity  54  is aligned with an elongated cavity  56  formed in the bottom of the hammer  52  along a central axis (not shown). The enlongated cavity  56  is generally-cylindrical with a pointed upper end  58  for accommodating the pin end of the jack  10 . 
         [0031]    The tool  48  includes a downwardly-protruding central core  60  that extends below the bottom edge  62  of the body  64  of the hammer  52 . As can be seen in the views of  FIGS. 3(   b ) and  3 ( c ), an open circular channel  66  is formed within the bottom edge  62  of the hammer  52  which surrounds the circumference of the open bottom of the elongated vertical cavity  56 . The inner side of the channel  66  communicates with the tapered sidewall  68  of the downwardly-protruding central core  60  of the hammer  52 . It will be seen below that the protruding central core  60  of the hammer  52  enables the jack  10  to be compressively-swaged to a panel by preventing the inward collapse of the barrel of the jack during swaging. 
         [0032]      FIG. 4  is a side elevation view of the swaging tool  48  with jack  10  arranged therein for fixation to a panel  70  of an electronic module while  FIGS. 5(   a ) and  5 ( b ) are enlarged cross-sectional views for illustrating the swaging of a jack to the panel  70  in accordance with an embodiment of the invention. As discussed above, prior art jacks are formed of thin sheet metal that is amenable to a swaging process that involves the creation of a rolled upper edge at the obverse side of a mounting panel. The creation of such a rolled edge relies upon (1) the relative thinness of the sheet metal of the barrel and (2) the use of a swaging tool (hammer) having a flat bottom with the inner edge of an open circular channel at the bottom thereof aligned with the unstressed barrel. Upon application of a downwardly-acting force by the hammer, the barrel is captured within the open circular channel and rolled outwardly to contact the upper surface of the mounting panel. 
         [0033]    Such prior art jacks and the associated swaging process often result in unsatisfactory fixation of jack to panel. They rely entirely upon the outward expansion of the portion of the barrel that resides within a port in the mounting panel. Such expansion necessarily occurs as the hammer advances downwardly and intimate contact takes place between the rolled edge of the barrel and the surface of the mounting panel adjacent the panel. The thinness of the material of the barrel prevents the creation of a knurled surface capable of contributing to resistance to the angular stresses that routinely result, for example, upon insertion and removal of electrical contacts. Also, the stretching of the free edge of the barrel can fracture the material of the barrel, if insufficiently resilient. Either can result in complete structural failure or periodic open-circuit connection between the shell of the jack and a metal panel. 
         [0034]    In contrast, the machined jack  10  and the swaging tool  48  cooperatively create a clamped connection to the mounting panel  70  that is highly resistant to angular stresses that are routinely encountered during use. 
         [0035]      FIG. 5(   a ) illustrates the jack  10  seated within the tool  48  for affixation to the mounting panel  70  during the initial stage of application of a downward-acting force from the hammer  52 . As can be seen, the upper edge  72  of the barrel  20 , whose inner surface  74  is aligned with the lower edge  76  of the tapered sidewall  68  of the downwardly-protruding central core  60  of the hammer  52  is received within the open circular channel  66  and, as a downwardly-acting force is applied by the hammer  52 , the upper edge  72  of the barrel  20  begins to bend outwardly. 
         [0036]    The barrel  20  is further downwardly compressed by the hammer  52  during swaging. Comparing the views of  FIGS. 5(   a ) and  5 ( b ), it can be seen that the material of the barrel  20  in the region of an upper edge  72  is guided outwardly by the tapered sidewall  68  of the protruding central core  60  of the hammer until the top of the upper edge  72  is fully captured within the open circular channel  66 . Thereafter, continued downward compressive force exerted by the hammer  52  causes some expansion in the width of the region of the upper edge  72  as shown in  FIG. 5(   b ). Such expansion is accompanied by outward bending of the portion of the barrel  20  throughout the thickness of the mounting panel  70 . Such outward bending is a result of the downward force combined with the guidance provided by the tapered sidewall  68  of the central core  60 . Keeping in mind that the outer surface of the barrel  20  is knurled, such outward bending causes the knurled surface of the barrel  20  to embed the inner periphery of the port of the panel  70  into which the jack  10  is being mounted whereby the outer surface of the barrel  20  is interlocked with the interior of such port. Such a bond is substantially more resistant to angular and rotational forces of the type routinely encountered during use than that afforded by a conventional jack that has been roll swaged to a mounting panel. 
         [0037]    Thus it is seen that the present invention provides a jack, method of affixation to a mounting panel and tool for mounting that offer a bond of improved quality to that offered by conventional jacks and known swaging processes. By utilizing the teachings of the invention, one may obtain a bond between jack and mounting panel that is substantially unaffected by repeated applications of torque to the jack. The bond thereby provided enables the electrical connection afforded by the jack to be essentially immune from shorting and other deleterious phenomena that would otherwise reflect degradation of contact between the jack and electrical ground. 
         [0038]    While this invention has been described with reference to its presently preferred embodiment, it is not limited thereto. Rather, the invention is limited only insofar as it is defined by the following set of patent claims and includes within its scope all equivalents thereof.