Abstract:
A self-adjusting antenna mounting assembly includes a protective base cap member which engages a vehicle antenna base and a contact extension cartridge. The contact cartridge includes a spring-biased hollow contact sleeve which biases the contact sleeve within a cavity so that it adjusts for varying lengths of contact pins which it engages. The contact sleeve has multiple arc-like segments which permit it to engage a contact pin of the antenna base, while not transferring any forces to it during installation.

Description:
BACKGROUND AND SUMMARY OF THE INVENTION 
     The present invention is directed generally to mobile telecommunications antenna mounting assemblies, and more specifically to a self-adjusting mobile telephone antenna mounting assembly which has a construction which reduces the likelihood of transfer of detrimental forces to the internal circuitry of the mounting assembly which may occur during installation of the assembly and antenna radiating element. 
     The number of mobile telephones in use in vehicles has risen dramatically in the past years and continues to increase. Many of these mobile telephones rely upon an antenna assembly mounted to the vehicle body. Often, the antenna assembly extends through an opening in the vehicle body and utilizes a portion of the vehicle body as a ground plane extension to enhance the ability of the antenna to receive and radiate radio frequency waves. The assembly typically includes an internal module mounted to the inside surface of the vehicle body and an external component which may extend through an opening cut in the vehicle body to engage the internal module. A cable extends between the vehicle mobile telephone and the internal module to connect them together. 
     These style mounting assemblies usually rely upon a cylindrical contact pin to connect the radiating element to the internal module. This contact pin extends up from the internal module through a protective cap to rigidly connect to the radiating element. These rigid connections are not easily adjustable and often may not compensate for the varying thicknesses encountered with different vehicle body panel portions. With such connections, the installation of either the protective base cap or radiating element may force the contact pin against the internal module and its associated internal circuitry, thereby increasing the likelihood of compromising the internal connections therebetween. 
     The present invention is directed to a mobile telecommunications antenna mounting assembly which overcomes the aforementioned disadvantages and which self-adjusts to the thickness of a vehicle mounting surface. It avoids the transfer of detrimental forces produced during installation to the internal circuitry of the internal antenna module and easily accommodates many standard antenna bases which use a central contact pin. 
     The antenna mounting assembly of the present invention comprises an external base and a protective base cap. The base cap includes a contact pin extension subassembly which may take the form of a cartridge-type assembly that extends through the base cap to provide an internal, self-compensating connection between the base contact pin and the antenna radiating element. The contact pin extension includes a biasing spring which extends within a recess of the pin body member and biases a circular collar, or hollow receptacle, axially outwardly from the body of the contact pin extension. 
     Inasmuch as vehicle body thicknesses vary between different makes and models of vehicles, the biasing spring permits selective axial movement of the contact collar to adjust for the distance which the base contact pin may project outwardly because of the vehicle body panel thickness. The contact pin extension engages the base cap so that the pin body member and base cap act as one component during installation. Accordingly, when the base cap is installed, there is no transfer of any twisting forces to the internal module circuitry of the antenna assembly because the contact receptacle freely spins while engaging the internal contact pin member. 
     Accordingly, it is a general object of the present invention to provide a universal mounting assembly for a mobile telecommunications antenna which self-adjusts for varying thickness of the vehicle body panels. 
     Another object of the present invention is to provide a mobile telecommunications antenna mounting apparatus having a spring-biased contact pin extension cartridge which rotatively engages the internal module contact pin to thereby eliminate the transfer of any detrimental forces to the contact pin during installation of the apparatus. 
     A further object of the present invention is to provide an improved universal pin mounting apparatus for a mobile telecommunications antenna which includes an external protective base cap having a cylindrical contact element extending axially through the base cap, the contact element having a cavity therein which houses a coil spring and a hollow contact sleeve, the contact sleeve being in rotatable contact with a rigid contact pin disposed in a base portion, the hollow sleeve element being axially biased within the contact element by the coil spring, whereby the spring permits the contact collar to displace within the cylindrical member cavity when engaged by a central contact pin of the antenna mounting base. 
     A still further object of the present invention is to provide a kit of parts for use in the assembly of a mobile telecommunications mounting assembly having an external base cap adapted to engage a base member which projects out from an opening in a vehicle body, the kit of parts including a contact pin body extension, a spring engaging the extension member and a contact sleeve slidably engaging the extension and spring, the extension member further engaging the base cap when installed such that the base cap and extension member rotate together as one component, whereby the spring permits self-adjustment of the extension member by movement of the contact receptacle along the pin body axis during installation. 
     These and other objects, features and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, wherein like reference numerals refer to like parts. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the course of this detailed description, reference will be made to the attached drawings in which: 
     FIG. 1 is a sectional view of a mobile telecommunications antenna assembly constructed in accordance with the principles of the present invention; 
     FIG. 2 is a sectional view of the contact pin subassembly of the antenna mounting assembly of FIG. 1; 
     FIG. 3 is an exploded perspective view of the contact pin subassembly of FIG. 2; 
     FIG. 4 is a sectional view of the mounting assembly of FIG. 1, in a condition where the vehicle body has a relatively small thickness, and, 
     FIG. 5 is a sectional view of the mounting assembly of FIG. 1 shown installed in place wherein the vehicle body has a relatively large thickness. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings, and particularly FIG. 1, a preferred embodiment is illustrated of a mobile telecommunications antenna apparatus 10 constructed in accordance with the principles of the present invention. The apparatus 10 is shown mounted in place on the body panel 12 of a vehicle. This panel 12 which may include a horizontal portion of the roof or a relatively vertical portion of a sidewall of the vehicle. The orientation of the body panel 12 does not affect the operation or benefits of the present invention. 
     A coupling unit 14 which contains the appropriate electronic circuitry such as a radiating circuit and an impedance matching circuit which permits the maximum high frequency energy to be radiated or absorbed by the radiating external radiating antenna element 15. A cable assembly 13 extends between the mobile telephone unit (not shown) of the vehicle and the coupling unit 14 mounted inside of the vehicle. The coupling unit 14 may be attached to the interior surface 20 of the vehicle body panel 12 for example, by a layer of adhesive disposed on a contact pad 22 of the unit 14 which opposes the body panel 12, so that the coupling unit 14 engages an opening 18 cut in the body panel 12. 
     A retaining means, illustrated as a ring element 24 may partially extend through the body panel opening 18 and may engage the coupling unit 14 in a manner well known in the art to retain the coupling unit 14 in place upon the body panel 12 so as to provide a sturdy base portion 26 for the apparatus. The base portion 26 projects past the exterior surface 28 of the vehicle body panel 12 and is engaged by the ring element 24 and is further engaged by a protective base cap 32 which may be threaded onto the base 26. In an alternate construction, the internal coupling unit 14 may extend through the body panel opening 18 and may be equipped with a threaded engagement portion 33 to provide a base for engagement by the base cap 32. 
     Regardless of the construction of the base portion 26, it typically includes an electrical contact member, such as a cylindrical contact pin 30 which extends from the base portion 26 and provides a means of operative electrical connection between the radiating element 15 and the internal circuitry of the coupling unit 14. The contact pin 30 is held within the base portion 26 in the general central portion of the base portion 26 and extends outwardly therefrom away from the body panel 16. The base cap 32 engages the base portion 26 at the threaded portion 33 to protect the contact pin 30 from atmospheric elements. 
     In an important aspect of the present invention, a contact pin extension, or assembly 34, provides an electrical connection between the radiating element 15 and the contact pin 30. FIGS. 2 and 3 best illustrate the details of this contact pin extension 34. The extension assembly 34 takes the form of a cartridge 35 which includes a cylindrical cartridge body 36 having a central cavity 38 extending axially therewithin from the rear end 40 of the cartridge body 36. The cavity 38 is shown as having two portions of different diameters D 1 , D 2  which are separated by an inner, annular shoulder 42. The first cavity portion 44 is the smaller of the two and is disposed entirely within the cartridge body 36, while the second portion 48 is the larger of the two and is disposed at the rear end 40 of the body 36. 
     A means for selectively biasing an engagement member 50 of the extension assembly 34 is illustrated as a coil spring 46 and extends through the cavity 38 and bears against a forward edge 45 of the cavity 38 at one end of the coil spring 46. The other end of the coil spring 46 bears against the contact pin extension assembly engagement member 50, shown as a hollow contact sleeve 51 which establishes an electrical connection between the antenna base portion contact pin 30 and the radiating element 15. In this regard, the coil spring 46, contact sleeve 51 and extension assembly body 36 may all be preferably formed from an electrically conductive material so that all three of these components form a conductive path from the antenna base contact pin 30 to the radiating element 15. 
     The contact sleeve 51 may contain one or a plurality of longitudinal slots 52 which separate the sleeve into multiple arcuate segments 53 which slightly flex outwardly, if necessary, to accommodate contact pins 30 which may have a slightly greater diameter slightly greater than that of the sleeve 50, but still maintain the contact sleeve segments 53 in touch with the contact pin 30 to maintain an electrical connection therebetween. The slots 52 also facilitate rotation of the contact sleeve 51 on the contact pin 30 when the entire assembly is installed in place upon the antenna base portion 26 by way of the ability of the sleeve segments 53 to flex. The contact sleeve 50 is free to rotate in place on the contact pin 30, and there is virtually no likelihood of the transfer of twisting forces to the internal circuitry of the antenna assembly because the contact sleeve 50 does not engage the contact pin in a rigid manner and because the contact sleeve 50 and the base cap 26 rotate together as one during installation. 
     The coil spring 46 provides a self-adjusting means for the assembly 10 in that the contact sleeve 51 has a spring engagement surface 54 disposed on its forward end 55 within the extension assembly 34. The engagement surface 54 bears against the rear end 47a of the coil spring 46. The contact sleeve 51 is preferably held in place within the cavity 38 by a suitable retainer, such as the elastomeric ring 56 which resides in an annular channel 57. This retainer 56 limits the reciprocating movement of the contact receptacle 50 within the cavity 38. The coil spring 46 applies an outward biasing force to the contact sleeve 51 and permits it to reciprocate within the cavity 38 in response to the forward end 31 of the base contact pin 30 impinging upon it to give the present invention its desired self-adjusting characteristics. 
     The cartridge body 36 is generally cylindrical and has three portions 64, 65 &amp; 66 defined in its outer surface by two circumferential shoulders 68, 69 formed therein. The first shoulder portion 68 is located near the rear of the cartridge body 36 and preferably forms a stop surface 70 which engages a similarly formed inner shoulder 72 of the base cap 32 and prevents the contact pin extension assembly 34 from being pushed through the base cap passage 37 during assembly. It also aligns the third body portion 66 with the base cap 32 to define a seat 16 against which the radiating element 15 sits when the assembly installation is completed. 
     The second body portion 65 is positioned between the other two portions 64, 66 and is provided to firmly engage the base cap passage 37. It includes a series of engagement members, shown as knurls 74, that extend radially outwardly from the outer surface thereof of the body portion 65. These knurls 74 cooperate with the base cap 32 and firmly engage the inner surface of the base cap passage 37 to provide an interference fit therebetween so that the extension assembly 34 and the base cap 32 operate as one element when they are assembled into the antenna base 26. The third body portion 66 is disposed forward of the second body portion 65 and includes a threaded cylindrical, outer surface 80 which engages a complimentary threaded bore 82 of the antenna radiating element 15. 
     The structure of the invention provides certain benefits and advantages as explained hereinafter. The coil spring 46 may be compressed in the cartridge body cavity 38 by the contact pin 30 of an antenna base 26 and therefore automatically adjusts to the thicknesses of the vehicle body panel 16. The outer diameter of the contact sleeve forward end 54 is approximately equal to that of the inner surface of the cartridge body cavity 38 so that an electrically conductive relationship is established between the contact sleeve 51 and the cartridge body 36. This electrically conductive relationship may be further enhanced by making the spring 46 from a conductive material to establish an additional conductive path between the cartridge body 36 and the contact sleeve 51. 
     The contact sleeve 51 slides over and maintains an electrical contact with the contact pin 30 regardless of body panel thickness because the contact sleeve 51 has a length sufficient to engage the contact pin 30 to accommodate situations where the contact pin 30 does not enter the cartridge body cavity 38 and also moves within the cavity to accommodate situations where the contact pin 30 enters the cartridge body cavity 38. 
     FIG. 4 illustrates one condition of benefit to the present invention in place or a vehicle wherein the vehicle body panel 12 has a relatively small thickness. The contact pin 30 may, in this situation extend slightly more from the base portion 26 because of the body panel thickness. In this instance, the forward end 31 of the contact pin 30 extends into the cavity 38 and engages the inner shoulder of the contact sleeve 51 and urges it along into the cartridge body cavity 38. The coil spring 46 resists this contact and maintains the contact sleeve 51 against the antenna base contact pin 30 in a conductive connection, while permitting the sleeve 51 to move axially within the cartridge body cavity 38, while electrical contact is maintained between the contact pin 30 and the contact sleeve 51. 
     In instances where the vehicle body panel has a relatively larger body panel thickness such as is illustrated in FIG. 5, the contact sleeve 51 extends rearwardly from the cartridge body and will engage a short contact pin 30 in the manner shown in FIG. 5. Because the contact sleeve 51 is formed from an electrically conductive material, a reliable connection is always maintained between the contact sleeve 51 with the antenna base contact pin 30. Thus it can be seen that base cap 32 and contact pin extension assembly 34 cooperate to form an integrated assembly which may be installed upon many different antenna bases without fear that the connection will be undesirable or that the installation will apply any detrimental forces to the internal circuitry of the antenna base 26 and internal coupling unit 14. 
     While the preferred embodiment of the invention has been shown and described, it will be understood by those skilled in the art that changes or modifications may be made thereto without departing from the true spirit and scope of the invention.