Abstract:
An apparatus for providing a guide and positioning mechanism for dictating retraction motion of a retractable member such as a retractable media jack. The apparatus is comprised of a “J-shaped” cam follower having a short end press-fit into a cam pushing with the longer end of the cam follower tracing out the path boundaries as dictated by a groove within a cam track. The cam bushing is comprised of a generally cylindrical cam axle through with the short end of the cam follower passes and an extended wedge-shaped extension for providing support to the extended longer portion of the cam follower. The longer portion of the cam follower is rotationally bounded by stops on each end of the wedge-shaped extension on the cam axle which keeps the long end of the cam follower radially bounded as the cam follower traces a catch and release path of the cam track during extension and retraction of the retractable member.

Description:
BACKGROUND OF THE INVENTION 
     1. The Field of the Invention 
     The present invention relates to the field of computers. More particularly, it relates to an interface between a connector and a communications card in a computer system, and specifically to a physical/electrical media connector interface for use with a PCMCIA-architecture communications card, such as used in laptop and notebook computers. 
     2. The Prior State of the Art 
     Many communication cards have means of interfacing with a media connector. The interface, or media jack, between the communication card and the media connector is typically retractable meaning that when the media jack is in use, it is extended out from the body of the communication card and when the media jack is not being used, it is retracted into the communication card. 
     The retractability of the media jack is accomplished by using a small rod, also called a cam follower, which follows a cam track as the media jack is extended and retracted. The cam follower is held in place by the media jack, but can move rotationally. The ability to rotate permits the cam follower to change position as it follows the cam track. The cam track guides the cam follower to certain positions as the media jack is extended or retracted. 
     In order for the described system to function, the cam follower must not only be able to rotate, but also capable of being held in a certain position. If the cam follower were to rotate freely, the media jack would no longer be able to be held in an extended or retracted position. Thus, while the cam track provides the necessary force to move the cam follower rotationally, the cam follower is held in place by a spring when the cam track is not acting on the cam follower. 
     The spring has two functions. First, the spring pushes against the media jack such that the media jack is held securely in an extended position. Second, the spring prevents the cam follower from rotating freely. Free rotation of the cam follower is prevented by placing one end of the spring against the body of the cam follower. The force of the spring against the cam follower holds the cam follower in the position dictated by the shape of the cam track. In this manner, the goal of retaining the media jack in a retracted position may be accomplished. In other words, the cam track guides the cam follower to a position that will keep the media jack retracted in the communications card. This design may be improved because of several reasons. 
     First, the cam follower and the spring are in constant contact and the cam follower continually rotates as the media jack is extended and retracted. This constant movement ultimately produces wear on the cam follower. As the wear increases, the ability of the spring to provide sufficient force to prevent the cam follower from freely rotating declines. In other words, if the cam follower is permitted to freely rotate then the media jack is no longer capable of being extended and retracted with regularity and if the media jack cannot be extended, the communications card is essentially useless. Likewise, if the media jack cannot be held in a retracted positon, the media jack is more likely to break, which renders the communications card useless. 
     Second, the cam follower is inserted into the side of the media jack and is only held in that position while the media jack is connected to the communications card. If the media jack were inadvertently or purposely removed from the communications card, it is likely that the cam follower would fall out of the media jack. The cam follower is very small and is unlikely to be found if it falls out of the media jack. If the cam follower is not found, then the media jack, when reconnected to the communications card, will remain in an extended position and is not capable of being retracted. 
     SUMMARY AND OBJECTS OF THE INVENTION 
     The present invention solves the problems evident in the prior art by using a cam bushing and changing the design of the cam follower. The cam track is essentially the same, but the physical design of the media jack is altered to accommodate and connect to the cam bushing. 
     In the present invention, a spring is no longer used to maintain the orientation of the cam follower. Rather, a cam bushing is used. The cam bushing acts as a bearing, which permits the cam follower to rotate as it is reoriented by the path of the cam track. The rotational orientation of the cam follower is maintained by the friction between the cam follower and the cam bushing. In other words, part of the cam follower is inserted into the cam bushing and the cam follower rotates about this axis. The fit between the cam bushing and the cam follower provides sufficient friction such that the cam follower will not rotate freely but may be reoriented by the cam track. 
     The problem of the cam follower falling out of the media connector is also solved by the present invention. The cam bushing is designed such that it has a compression fit with the media jack. The compression fit is designed such that the cam follower may still rotate, but the cam bushing will not fall out of the media jack. Because the small cam follower is connected to the cam bushing, the cam follower will likewise not fall out and be lost. 
     It is therefore an object of the present invention to prevent a cam follower from falling out of a media connector. 
     It is yet another object of the present invention to securely attach the cam bushing to the media jack. 
     It is a further object of the present invention to ensure proper orientation of the cam follower. 
     Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. These and other objects and features of the present invention will become more fully apparent from the following description and appended claims, or may be learned by the practice of the invention as set forth hereinafter. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In order that the manner in which the above-recited and other advantages and objects of the invention are obtained, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments of the invention and are not therefore to be considered limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which: 
     FIG. 1 is a perspective view of a cam follower; 
     FIG. 2 is a perspective view of a cam bushing; 
     FIG. 3 is a perspective view of the cam follower connected to the cam bushing and the cam track; and 
     FIG. 4 is a perspective view of the cam follower, the cam bushing and the media jack. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A system is provided that combines the cam bushing with other parts such that the position of the cam follower is maintained. The cam bushing and the related parts are shown in FIGS. 1 through 4. FIGS. 1 and 2 will be described in terms of their structure, while FIGS. 3 and 4 will be described in terms of function. 
     FIG. 1 is a perspective view of a cam follower  20 . Cam follower  20  has a short arm  22  and a long arm  24  connected by a bar  26 . Cam follower  20  is generally U-shaped and is generally made of metal. The ratio of the length of short arm  22  to the length of long arm  24  can be varied as needed. The function of cam follower  20  is discussed in connection with FIGS. 3 and 4. 
     FIG. 2 is a perspective view of a preferred embodiment of a cam bushing  40 . Cam bushing  40  is comprised of the following parts: a back  43  including a cam axle  44  and a cam sill  46 , an aperture  42 , an arm stop  48 , a front  41 , a generally curved top surface  47 , and an axle length  49 . Cam axle  44  is preferably cylindrical in shape. Aperture  42  is preferably located in cam axle  44  and is preferably cylindrical in shape. Cam sill  46  has a curved surface and arm stop  48  extends up on both sides of cam sill  46 . Front  41  is substantially flat. The shape and function of cam bushing  40  is discussed in connection with FIGS. 3 and 4. 
     FIG. 3 is a perspective view of a cam track  50  along with a perspective view of cam bushing  40  coupled with cam follower  20 . In the embodiment of the invention shown in FIG. 3, short arm  22  is inserted into aperture  42 . Aperture  42  is configured to receive short arm  22  and aperture  42  has substantially the same shape as short arm  22 . The friction between short arm  22  and aperture  42  prevents cam follower  20  from rotating in aperture  42 . Note that aperture  42  may have any suitable shape that creates sufficient friction to prevent short arm  22  from rotating in aperture  42 . By the same token, short arm  22  may have any suitable shape that permits rotation. It is possible that short arm  22  and aperture  42  do not have substantially the same shape. In the preferred embodiment, however, short arm  22  and aperture  42  have substantially the same shape. The friction between short arm  22  and aperture  42  prevents short arm  22  from rotating freely. In other words, cam bushing  40  is designed to prevent cam follower  20  from freely rotating in aperture  42  Note that short arm  22  may rotate in aperture  42  when acted upon by an external force. In fact, it is necessary for cam follower  20  to rotate about short arm  22  when cam follower  20  is coupled with cam bushing  40 . 
     Cam track  50  provides the means or external force for rotating cam follower  20  about short arm  22 . When short arm  22  is fully inserted into aperture  42 , long arm  24  extends past front  41 . Cam bushing  40  is oriented such that the portion of long arm  42  that extends past front  41  rests in a groove  51 . As cam bushing  40  is moved alongside cam track  50  in a parallel fashion, groove  51  provides an external force which pushes against long arm  24 . This external force against long arm  24  causes cam follower  20  to rotate about short arm  22  while the friction between short arm  22  and aperture  42  prevents cam follower  20  from rotating freely. 
     The motion of cam bushing  40  relative to cam track  50  is as follows. The direction of cam bushing  40  will be described in terms of left and right to correspond to FIG.  3 . First, cam bushing  40 , with the end of long arm  24  in groove  5 l, moves left towards a catch  56 . Cam track  50  is designed such that as cam follower  20  moves toward catch  56 , long arm  24  will follow a catch path  52 . As long arm  24  reaches the bottom of catch path  52 , long arm  24  is reoriented by the shape of catch path  52 . Then cam bushing  40  is moved towards the right. Due to the reorientation of long arm  24 , catch  56  prevents cam bushing  40  from moving any further to the right. Cam bushing  40  is then moved to the left. As cam bushing  40  moves to the left, the shape of a release path  54  reorients long arm  24 . When cam bushing  40  is moved to the right, long arm  24  is oriented such that long arm  24  follows release path  56 . Cam bushing  40  is now free to move to the right and as cam bushing moves to the right, the shape of groove  51  again moves long arm  24  such that when cam bushing  40  is moved to the left, the above process will occur again. This process is continually repeated as needed. The purpose of this design is to permit media jack  60 , shown in FIG.  4  and connected to cam bushing  40 , to be extended and retracted. When cam bushing  40  is prevented from moving to the right by catch  56 , media jack  60  is retracted. When cam bushing is moved to the right, media jack  60  is extended. 
     As further demonstrated in FIG. 3, when cam follower  20  is coupled with cam bushing  40  by inserting short arm  22  in aperture  42 , long arm  24  is positioned above cam sill  46 . In the preferred embodiment, cam sill  46  extends up from cam axle  44 . Cam sill  44 , however, need not be physically connected to cam axle  44 . Cam sill  46  has a generally curved top surface  47 . 
     Top surface  47  of cam sill  46  has at least two functions. First, top surface  47  prevents long arm  24  from bending or becoming oriented incorrectly. Long arm  24  of cam follower  20  is small and flexible and the absence of cam sill  46  would allow long arm  24  to bend. If long arm  24  is allowed to bend, then catch  56  will not be able to prevent cam bushing  40  from moving to the right. In other words, cam sill  46  keeps long arm  24  rigid and ensures that cam bushing  40  is kept in a retracted position. 
     The second function of top surface  47  of cam sill  46  is to permit cam follower  20  to rotate about short arm  22 . Because short arm  22  is held stationary by aperture  42 , short arm  22  becomes an axis about which cam follower  20  rotates. When cam follower  20  rotates, long arm  24  traces an arc as it moves along top surface  47 . Cam sill  46  is designed to allow cam follower  20  to rotate. For this reason, top surface  47  of cam sill  46  is generally curved but can be of any suitable shape. In sums cam sill  46  can be any shape that allows long arm  24  to rotate about short arm  22  and prevents long arm  24  from bending and losing its orientation in cam track  50 , or more specifically groove  51 , catch path  52  and release path  54 . 
     Top surface  47  has arm stop  48  located at either side extending up from top surface  47 . Arm stop  48  prevents long arm  24  from rotating too far in either direction. Arm stop  48  may extend along the entire side of top surface  47 , or may extend along only a portion of top surface  47  as illustrated in FIG.  3 . 
     FIG. 4 is a perspective view of a media jack  60  and a perspective view of cam bushing  40  coupled with cam follower  46 . FIG. 4 also illustrates how cam bushing  40  connects to media jack  60 . Cam bushing  40  connects to media jack  60  via a recess  62 . Recess  62  is preferably hexagonal in shape and has a depth  66  depth to receive cam axle  44 , which is preferably cylindrical in shape. Axle length  49  of cam axle  44 , as shown in FIG. 1, is sufficient to permit a secure compression fit with recess  62 . Cam length  49  is substantially and preferably the same as depth  66 . Recess  62  and cam axle  44  are compressed together such that cam bushing  40  is securely connected to media jack  60 . The respective shapes of cam axle  44  and recess  62  can vary, as long as cam bushing  40  is securely connected to media jack  60 . This connection may be accomplished by a compression fit as illustrated in FIG. 4, or by any other equivalent means. 
     A trough  64  is connected to recess  62 . Trough  64  is designed to provide space beneath recess  62  such that cam follower  20  may rotate in cam bushing  40 . The shape of recess  62  and trough  64  is substantially the same as the shape of cam axle  44  and cam sill  46 . The major differences between the two shapes is that recess  62  is configured to form a compression fit with cam axle  44  and trough  64  is designed to permit cam follower  20  to rotate while cam bushing  40  is securely connected to media jack  60 . When cam bushing  40  is connected securely to media jack  60 , front  41  of cam bushing  40  is substantially flush with the side of media jack  60 . Also, long arm  24  extends from the side of media jack  60  Long arm  24  is capable of rotating about short arm  22  and follows cam track  50 , as shown in FIG. 3, as media jack  60  is extended and retracted in a communications card. Note that a spring  70  ensures that media jack  60  will be securely held in one of two positions. Media jack is either fully extended by spring  70  or media jack  60  is retracted because, as illustrated in FIG. 3, long arm  24  is against catch  56  and in this manner spring  70  is prevented from extending media jack  60 . Note that the absence of cam sill  46  would allow the force of spring  70  to bend long arm  24 , which would prevent media jack  60  from being held in a retracted position. 
     The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.