Machine element or mechanism – Elements – Cams
Utility Patent
1998-11-30
2001-01-02
Luong, Vinh T. (Department: 3682)
Machine element or mechanism
Elements
Cams
C074S567000, C439S055000
Utility Patent
active
06167781
ABSTRACT:
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.
REFERENCES:
patent: 2345650 (1944-04-01), Attwood
patent: 3802725 (1974-04-01), Hill
patent: 5183404 (1993-02-01), Aldous et al.
patent: 5428982 (1995-07-01), Hinterlechner et al.
patent: 5543787 (1996-08-01), Karidis et al.
patent: 5959715 (1999-09-01), Jaffelin
Francis Dexter
Kunz Ryan
Madsen Brent
Oliphant David
Randall Josh
3Com Corporation
Luong Vinh T.
Workman & Nydegger & Seeley
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