Abstract:
A connection part has at least two matingly interengaging contact pieces that electrically connect the central conductor of a coaxial cable without soldering or trimming. In the preferred embodiment, the connection part includes a bifurcated segment and another segment resiliently disposed between the bifurcated segment. A jig is inserted through an opening into the connection part, separating and pushing the segments apart, creating a space where the central conductor of a coaxial cable is inserted. The central conductor is pressed against a groove formed by an arcuate section of the connection part segments. When the jig is removed, the resilient action of the segments grip and bend the central conductor holding it firmly and electrically connecting it to the connection part. Bendable cover pieces close the opening. An insulative covering closes and protects the coaxial connector. Grounding arms are connected to the shielding conductor of the coaxial cable and project from slots in the insulative covering. A clamping section clamps the outermost layer of the coaxial cable securing it to the coaxial connector.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a coaxial connector for connecting a coaxial cable to electrical equipment or the like. More particularly, it relates to a coaxial connector whose central contact makes resilient contact with a central conductor of a coaxial cable to establish electric connections between the connector and the cable without the use of solder and without the need to trim the central conductor after connecting. 
     Referring to FIG. 12, it is customary in the prior art to connect a coaxial cable  104  and a coaxial connector  100  by soldering the tip of a central conductor  105  to a plug pin  103 . A clamping part  107  clamps a shielded conductor  106  that surrounds central conductor  105 . 
     The following is a brief description of a prior art procedure for connecting coaxial connector  100  to coaxial cable  104 . To begin with, plug pin  103 , ultimately serving as a central contact, is forced into an insulating housing  102 . An external contact  101  is slid over and fixed to insulating housing  102 . Then, central conductor  105  of coaxial cable  104  is prepared by stripping and exposing a long portion of central conductor  105  and stripping and exposing a much smaller portion of shielded conductor  106 . The stripped forward end portion is inserted into plug pin  103  and passes through a hole  108 . Shielded conductor  106  is clamped by clamping part  107 . Clamping part  107  electrically connects shielded conductor  106  to external contact  101 . Coaxial cable  104  is also clamped by clamping part  107  along with shielded conductor  106 , and hence it is fixed to coaxial connector  100 . 
     Central conductor  105  is soldered to the tip of plug pin  103 . The portion of central conductor  105  projecting out of hole  108  is trimmed away. Next, an insulating cover  109  is mounted on the connector assembly with a contact piece  110  of external contact  101  protruding through a cutout (not shown) in insulating cover  109 . The above is atypical prior art procedure to connect coaxial connector  100  to coaxial cable  104 . 
     With the conventional coaxial connector it is necessary to solder central conductor  105  to the tip of plug pin  103 . After soldering, it is also necessary to cut off the portion of central conductor  105  that projects beyond hole  108 . The soldering and cutting requirements complicate the assembly of a prior art coaxial connector to a coaxial cable and hence increases manufacturing costs. It also increase the time it takes to assemble the coaxial connector in the field. In addition, such solder joints are a frequent cause of poor connections. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     It is an object of the invention to provide a coaxial connector that overcomes the limitations of the prior art. 
     It is another object of the invention to provide a coaxial connector that is easily assembled. 
     It is another object of the invention to provide a coaxial connector which does not require soldering, thus reducing the cost and time required to connect a coaxial cable to a connector. 
     It is another object of the invention to provide a coaxial connector which does not require trimming after connecting, thus reducing the time spent connecting a coaxial cable to a connector. 
     It is yet another object of the invention to provide a coaxial connector that is cheaper to manufacture than the prior art. 
     Briefly stated, the present invention provides a connection part that has at least two matingly interengaging contact pieces that electrically connect the central conductor of a coaxial cable without soldering or trimming. In the preferred embodiment, the connection part includes a bifurcated segment and another segment resiliently disposed between the bifurcated segment. A jig is inserted through an opening into the connection part, separating and pushing the segments apart, creating a space where the central conductor of a coaxial cable is inserted. The central conductor is pressed against a groove formed by an arcuate section of the connection part segments. When the jig is removed, the resilient action of the segments grip and bend the central conductor holding it firmly and electrically connecting it to the connection part. Bendable cover pieces close the opening. An insulative covering closes and protects the coaxial connector. Grounding arms are connected to the shielding conductor of the coaxial cable and project from slots in the insulative covering. A clamping section clamps the outermost layer of the coaxial cable securing it to the coaxial connector. 
     According to an embodiment of the invention there is provided a coaxial connector comprising: a plug pin having a connection part; the connection part having at least two contact pieces that matingly interengage; and means for permitting urging of a central conductor against metal springback between the at least two contact pieces whereby the central conductor is positionable between same, the central conductor is resiliently retained between the at least two contact pieces by the metal springback without requiring soldering for mechanical and electrical connection. 
     According to another embodiment of the invention, there is provided a coaxial connector for attachment to a coaxial cable which has been prepared by stripping back an outer conductor exposing a portion of an inner conductor, comprising: an external contact; a plug pin coaxially disposed in the external contact; means for electrically isolating the external contact from the plug pin; the plug pin having a plug end extending beyond an end of the external contact; the external contact having at least one external contact surface for contacting a socket; the plug pin also having a connection part disposed at an other end; the connection part having at least two contact pieces that matingly interengage; and means for urging a central conductor against metal springback between the at least two contact pieces whereby the central conductor is positionable between same, the central conductor is resiliently retained between the at least two contact pieces without requiring soldering for mechanical and electrical connection. 
     According to yet another embodiment of the invention, there is provided a coaxial connector comprising: a plug pin having a connection part; the connection part having at least two contact pieces that resiliently interengage; and means for temporarily urging the at least two contact pieces apart forming a channel, whereby the central conductor is insertable in the channel and once the central conductor is inserted in the channel, the at least two contact pieces resiliently move back together deforming the central conductor, resiliently retaining the central conductor against axial forces without requiring soldering for mechanical and electrical connection. 
     The above, and other objects, features and advantages of the present invention will become apparent from the following description read in conjunction with the accompanying drawings, in which like reference numerals designate the same elements. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a plan view, partly cut away, illustrating the coaxial connector according to the present invention with a coaxial cable connected thereto. 
     FIG. 2 is an enlarged plan view of a connection part  11  of the coaxial connector depicted in FIG.  1 . 
     FIG. 3 is a longitudinal sectional view of the coaxial connector of FIG. 1 taken along its center axis. 
     FIG. 4 is a cross sectional view of the coaxial connector of FIG. 1, showing the connection part  11  with no central conductor of the coaxial cable connected thereto. 
     FIG. 5 is a cross sectional view of the coaxial connector, showing how a central conductor  41  of the coaxial cable is inserted into the connection part  11  by means of a jig  50 . 
     FIG. 6 is a cross sectional view of the coaxial connector, showing the connection part  11  having received in its groove  15  the central conductor  41  of the coaxial cable. 
     FIG. 7 is a cross sectional view of the coaxial connector, showing the connection part  11  covered with a cover piece  28  of an external contact  2 . 
     FIG. 8 is a plan view of a plug pin  4  that serves as the central contact  4 . 
     FIG. 9 is a plan view of the external contact  2 . 
     FIGS.  10 ( a ) through  10 ( e ) are schematic diagrams illustrating a sequence of steps involved in assembling the coaxial connector according to the present invention. 
     FIGS.  11 ( a ) and  11 ( b ) are a front and a bottom view of the jig  50 , respectively. 
     FIG. 12 is a longitudinal sectional view depicting a conventional coaxial connector with a coaxial cable connected thereto. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIGS. 1,  3  and  8 , a coaxial connector  1  includes a cylindrical insulating housing  3 . A plug pin  4  is supported in a cylindrical hollow  32 . Cylindrical hollow  32  is disposed in insulating housing  3 . An external contact  2  slides over insulating housing  3 . An insulating cover  7  covers external contact  2 . An insulating cap  8  covers the rearward end of insulating cover  7 . 
     Plug pin  4 , which serves as a central contact, is produced by stamping or die-cutting a metal sheet and bending it into a slender cylinder. The forward portion (left-hand side) of plug pin  4  is a plug contact part  10  for contact with a signal terminal of a mating connector (not shown). The rearward portion of plug pin  4  is a connection part  11  for electrical connection with a central conductor  41  of a coaxial cable  5 . 
     Referring to FIGS. 2-4 and  8 , connection part  11  includes a U-shaped contact piece body  16 , a first contact piece  12 , and a second contact piece  13 . First contact piece  12  and second contact piece  13  are matingly interengageable. U-shaped contact piece body  16  is formed by arcuately bending the rearward portion of plug pin  4  about a center axis O longitudinally parallel to plug pin  4 . First and second contact pieces  12  and  13 , respectively, are formed by bending both end portions of contact piece body  16  around center axis O. 
     Second contact piece  13  is bifurcated providing parallel segments with first contact piece  12  disposed between them. First and second contact pieces  12  and  13  are inwardly bent from both sides of contact piece body  16  so that they matingly interengage around center axis O. Plug pin  4  fits into insulative housing  3  in the same direction (from left to right in the Figs.) in which coaxial cable  5  is inserted into coaxial connector  1 . Plug pin  4  is longitudinally fixed within insulating housing  3 . This arrangement ensures that center axis O of plug pin  4  is in alignment with the insertion direction coaxial cable  5  and substantially in alignment with the direction of the projection of central conductor  41 . The bifurcated second contact piece  13  has its two segments arcuately bent forming an L-shaped groove  15  for positioning central conductor  41 . 
     Referring to FIGS. 3,  9  and  10 ( a )-( e ), external contact  2  is formed as a cylinder covering the surface of insulating housing  3  described later. External contact  2  has a plurality of contact pieces  26  extending obliquely rearward from its forward end portion. Contact pieces  26  each have a circularly arcuate extremity, which make contact with a grounding terminal (not shown) of a mating connector (not shown.) At the bottom of the forward end portion of external contact  2 , there is an inward lug  23  that engages a stepped portion of insulating housing  3 , securing it to external contact  2 . 
     A pair of cover pieces  28  are integrally formed on contact piece  2 . A U-shaped outer clamping portion  22  and a cable sheath clamping portion  17  are also integrally formed on contact piece  2 . Cover pieces  28  cover the upper portion of connection part  11 . Outer clamping portion  22  clamps a shielded conductor  42  of coaxial cable  5 . Cable sheath clamping portion  17  clamps the outermost layer of the cable sheath of coaxial cable  5 . 
     A coupling piece  24  integrally extends from the rear of external contact  2 . Coupling piece  24  is generally U-shaped and extends beyond outer clamping portion  22 . Coupling piece  24  also includes a U-shaped inner clamping portion  21 . When shielded conductor  42  is clamped by outer clamping portion  22 , inner clamping portion  21  is pressed into coaxial cable  5  between an inner insulator  40  and shielded conductor  42 . 
     External contacts  2  are manufactured connected to other external contacts  2 . Each external contact  2  includes a carrier  27  joined to an intermediate portion of coupling piece  24 . Each external contact  2  is severed from the others prior to assembling. 
     Referring now to FIGS. 3,  4  and  10 ( e ), insulating housing  3  has a cylindrical hollow  32  extending longitudinally from the front to the back of insulative housing  3 . Along the outer periphery of insulating housing  3 , a stepped portion  31  engages inward lug  23  of external contact  2 . An upward opening cutout  33  is disposed in the rear portion of insulating housing  3 . Central conductor  41  can easily be pressed into contact with connection part  11  through cutout  33 . 
     Insulating cover  7  is generally cylindrical and covers the outer peripheral surface of external contact  2 . Contact pieces  26  protrude through cutouts (not shown) in insulating cover  7 . Insulating cover  7  protects external contact  2  and fixes it to insulating housing  3 . Insulating cover  7  has a projection  51  on its rearward end. Insulating cover  7  has a through hole  52  at its forward end through which plug pin  4  passes. 
     The rearward end of insulating cover  7  is covered with insulating cap  8 . Insulating cap  8  has a hole  60  for receiving projection  51  of insulating cover  7 . Coaxial cable  5  is inserted into coaxial connector  1  through a through hole  61  in insulating cap  8 . 
     Referring to FIGS. 3-7 and  10 ( a )-( e ) coaxial connector  1  is assembled by pressing plug pin  4  into cylindrical hollow  32  through the rearward end of same. External contact  2  is formed by stamping or die-cutting a sheet metal into a contact blank and bending it as described supra. Then, the assembly shown in FIG.  10 ( a ) is inserted into external contact  2  from the frontward end of external contact  2 . Lug  23  slides against stepped portion  31  of insulating housing  7 . Lug  23  engagingly secures external contact  2  to the outside of insulating housing  3 . 
     Shielded conductor  42  and central conductor  41  of coaxial cable  5  are stripped. Central conductor  41  is connected to connection part  11  and shielded conductor  42  is connected to external contact  2 . The connection between central conductor  41  and connection part  11  will be described in detail infra. 
     Central conductor  41  of coaxial cable  5  is initially positioned slightly above connection part  11  near central axis O as coaxial cable  5  is inserted into external contact  2  from its rearward end. Accordingly, stripped central conductor  41  lies just above contact pieces  12  and  13  of connection part  11 . Next, a jig  50 , is guided through cutout  33  in insulating housing  3 . In this position, central conductor  41  is straddled by pressing projections  53  of jig  50 . The structure of jig  50  is described infra. As jig  50  is guided into the position shown in FIG. 5, first and second contact pieces  12  and  13  are pressed apart by the bottom of jig  50 . Central conductor  41  is guided down and aligned along central axis O by jig  50  into groove  15  defined by the two segments of second contact piece  13 . 
     Upon removal of jig  50 , first and second contact pieces  12  and  13  go back towards their initial positions by their own resiliency. Central conductor  41  is guided down against groove  15  and is urged against second contact piece  13  by first contact piece  12 . This securely positions central conductor  41  in groove  15 . Central conductor  41  is firmly held between first and second contact pieces  12  and  13  which are electrically connected to plug pin  4 . Central conductor  41  is easily bent by a slight external force. Thus the resilient action of first and second contact pieces  12  and  13  bends the small portion of central conductor  41  that is held between first and second contact pieces  12  and  13 . This provides a secure electrical connection between central conductor  41  and connection part  11  at a plurality of places preventing central conductor  41  from easily dislodging. 
     Referring to FIGS. 5 and 11, jig  50  has downward projections  53  which straddle first and second contact pieces  12  and  13  when jig  50  is inserted through cutout  33 . Central conductor  41  is straddled by projections  53  as jig  50  is inserted and is pushed down into position by a notched portion  70 . Projections  53  push and separate first and second contact pieces  12  and  13  allowing central conductor  41  to be properly seated along center axis O. First and second contact pieces  12  and  13  resiliently grip central conductor  41  as jig  50  is removed. 
     Referring now to FIG.  10 ( c ), shielded conductor  42  and external contact  2  are connected to each other by inserting inner clamping portion  21  between inner insulator  40  and shielded conductor  42 . Next, outer clamping portion  22  and inner clamping portion  21  clamp shielded conductor  42  and inner insulator  40  together. As a result, shielded conductor  42  of coaxial cable  5  and external contact  2  of coaxial connector  1  are securely fixed and electrically connected to each other. Following this, sheath clamping portion  17  clamps the outer sheath of coaxial cable  5 . This securely fixes coaxial cable  5  to external contact  2 . 
     Referring now to FIGS.  9  and  10 ( c )-( d ), once coaxial cable  5  is connected to external contact  2 , coupling piece  24  is severed from carrier  27  at a position just behind sheath clamping portion  17 . Inner clamping portion  21 , once clamped, is firmly fixed by outer clamping portion  22  to coaxial cable  5  and will not fall out when coupling portion  24  is severed. 
     Referring now to FIGS.  7  and  10 ( e ), once the above has been accomplished, cover pieces  28  of external contact  2  are bent from the positions indicated by the broken lines along a radius of the cylindrical portion of external contact  2 . In this way, cover pieces  28  cover the opening above connection part  11 . This shields central conductor  41  from the outside and protects it against unwanted radiation and external noise. Then, insulating cover  7  is slid over external contact  2  from the front until the rearward end of cover  7  engages with insulating cap  8 . Plug pin  4  projects out of through hole  52 . Contact pieces  26  protrude through cutouts (not shown) in cover  7 . Insulating cover  7  and insulating cap  8  are fixed to each other. 
     Coaxial connector  1  is connected to a mating connector (not shown.) Pin plug  4  makes contact with a central terminal (not shown) of mating connector. Contact piece  26  makes contact with a grounding terminal (not shown) of mating connector. 
     Because central conductor  41  of coaxial cable  5  is electrically connected to plug pin  4  of coaxial connector  1  by the resilient action of connection part  11 , coaxial connector  1  is easily assembled to coaxial cable  5  without soldering and severing central conductor  41  as is required in the prior art. This reduces the manufacturing costs of coaxial connector  1 . 
     Central conductor  41  of coaxial cable  5  is gripped by resilient first and second contact pieces  12  and  13  and is positioned in groove  15 . This ensures that central conductor  41  is securely connected both mechanically and electrically. This arrangement prevents central conductor  41  from dislodging during use. 
     Because second contact piece  13  is bifurcated, two segments firmly grip central conductor  41  in combination with first contact piece  12  which is matingly disposed between the two segments. This ensures that connection between central conductor  41  and connection part  11  is secure and prevents central conductor  41  from dislodging during use. 
     While the above descriptions have utilized a plug pin (serving as a central contact) and a connection part that are integrally formed, it is not necessary that they be a unitary structure using the same material. One skilled in the art would recognize that they could be formed as separate parts as long as they are electrically connectable. 
     Furthermore, although groove  15  has been described to be defined by second contact piece  13 , it may also be formed on first contact piece  12 . 
     Additionally, jig  50  does not have to be used to place central conductor  41  in position. Central conductor  41  may be manually inserted axially into position after jig  50  pushes first and second contact pieces  12  and  13  apart. Contact pieces  12  and  13  are released to grip central conductor  41  in position. Outer clamping portion  22  may be crimped into position on shielded conductor  42  either before or after clamping central conductor  41 . Although the preferred embodiment includes jig  50 , it is possible to spread first and second contact pieces  12  and  13  using nonspecific tools such as a screwdriver or nail without departing from the scope or spirit of the invention. 
     Contact pieces  12  and  13  are not limited specifically to the configurations described above. Other examples of contact pieces include a trifurcated contact piece providing three segments matingly interengaging another bifurcated contact piece with the segments firmly received between them. 
     First and second contact pieces  12  and  13  matingly engage each other, bending central conductor  41  which locks it into position within groove  15 . This ensures sufficient contact pressure is applied to central conductor  41 . Because central conductor  41  is supported in groove  15 , it will remain in position even if subjected to external forces. 
     Moreover, since connection part  11  is resiliently connected to central conductor  41  by utilizing the resiliency of a band-shaped metal sheet which extends over the entire length thereof, only a small amount of force is required to insert central conductor  41  into coaxial connector  1 . Therefore, even if central conductor  41  is readily bendable, it can be connected to connection part  11 . Furthermore, once connected, central conductor  41  bends between end portions of first and second contact pieces  12  and  13 . This establishes electrical connections at a plurality of positions along central conductor  41 . Hence, the reliability of the connection is increased. 
     There are many types of coaxial cables in use. Some coaxial cables lack an outer insulative covering. The invention works with all types of coaxial cables. On coaxial cables lacking an outer insulative layer, both outer clamping portion and cable sheath clamping portion are crimped around the outer conductive layer. 
     Having described preferred embodiments of the invention with reference to the accompanying drawings, it is to be understood that the invention is not limited to those precise embodiments, and that various changes and modifications may be effected therein by one skilled in the art without departing from the scope or spirit of the invention as defined in the appended claims.