Abstract:
A receptacle for completing an electrical circuit between first and second devices, such as an electronic button and an interface circuit. The receptacle comprises a column moveable within a structure defining a channel having first and second ends, the column includes an electrically conductive contact engageable by the first device at the first channel end. An electrical terminal is spaced from the column at a second channel end, the electrical terminal being electrically connectable to the second device. A connector is electrically connected to the contact and extends within the channel toward the terminal, such that upon engagement of the contact by the first device, the connector electrically engages the terminal, thereby completing the electrical circuit between the devices. A second electrically conductive contact is located within the channel adjacent the column which is engageable by the first device. A second terminal is spaced from the column at the second channel end, the second terminal being electrically connectable to the second device and also being connectable to the second electrically conductive contact by a ground spring arrangement.

Description:
TECHNICAL FIELD 
     The invention relates generally to electronic receptacles and more specifically to a receptacle in an electronic enclosure for use with an electronic button. 
     BACKGROUND OF THE INVENTION 
     Dallas Semiconductor Corporation of Dallas, Tex. has created a series of electronic buttons which are marketed under the trademark &#34;Touch Memory™.&#34; These electronic buttons consist of a semiconductor chip secured within a coin-shaped stainless steel container which is approximately 16.3 millimeters in diameter and 5.8 millimeters thick, similar in appearance to a large watch battery. Just like a watch battery, these electronic buttons are circular in shape and constructed with joined circular female and male members. The female member comprises one surface of the container and its sides, while the male member is designed to be inserted into the female member to comprise the second surface of the container. The electronic button is assembled such that the female and male members are electrically insulted from one another, thus enabling the female and male members to serve as separate electrical terminals when the electronic button is in use, similar to the positive and negative terminals of a watch battery. 
     When the electronic button is assembled, a semiconductor chip having a ground and a signal pin is secured within the container. The semiconductor chip&#39;s ground pin is electrically connected to the female member and the semiconductor chip&#39;s signal pin is electrically connected to the male member. This allows the female member to serve as the ground terminal and the male member to serve as the signal terminal for the encased semiconductor chip. 
     The electronic button&#39;s internal semiconductor chip is uniquely designed such that by attaching the electronic button ground terminal to ground and simultaneously attaching the signal terminal to an appropriately activated electrical signal, the electronic button is able to deliver data stored in the semiconductor chip onto the signal line and/or receive data sent on the signal line. One of the unique features of the electronic button is that data may be delivered and/or received in a very brief period of time, thus only requiring a momentary contact with the ground and signal terminals. In one application, a &#34;read-only&#34; electronic button can be programmed with a unique identification number which enables the electronic button to serve as an electronic key. In another application a &#34;read/write&#34; electronic button may be used to record and keep track of a patient&#39;s medical data which may be placed on a bracelet and worn by the patient during the patient&#39;s hospital stay. The internal semiconductor chip may be designed with various other functionalities and used in many applications. 
     One of the problems encountered with the use of electronic buttons is the design of an acceptable receptacle to receive the electronic button. The receptacle, upon receipt of the button, makes the appropriate ground and signal contacts with a device to which the button interfaces, such that data and/or signals may be transferred between the interface device and the button&#39;s internal semiconductor chip. Various receptacles are available that utilize a circular electronic button retainer, hardwired to the interface device and having an outer ground contact and an inner signal contact into which the electronic button is inserted. Once inserted, the ground and signal contacts complete an electrical circuit through the electronic button to activate its internal semiconductor chip and the transfer of data to or from the interface device. 
     While the foregoing receptacle design is suitable for most applications, drawbacks exist when the design is employed in connection with certain types of electronic enclosures. For example, the ground and signal contacts of the receptacle, when not in operation with the electronic button, often remain exposed on the face of the enclosure thereby creating a potential for short circuit activation and/or damage to the interface device connected to the receptacle. Further, the single-piece construction of the receptacle, and the hard-wired electrical connections between the receptacle and the interface device, make it difficult to incorporate the receptacle into an electronic enclosure that has a removable cover. In particular, upon removal of the cover to which the receptacle is mounted, the electrical wiring extending between the receptacle and the interface device must be disconnected, or alternatively the wiring must be of sufficient length to avoid inadvertent disconnection. 
     The above problems associated with existing electronic button receptacles are of particular concern when the electronic enclosure involved is the housing of a personal computer. Generally, electronic buttons are used with personal computers as an electronic key for verifying access to the system and for other intelligent data transfer operations. The receptacle of the electronic button is typically incorporated into the front bezel, i.e, the removable cover, of the computer housing. The receptacle is then connected by wiring to interface circuitry within the computer to enable data communication between the electronic button and the computer. Since most personal computers reside on a desktop surface, there is an increased risk of conductive material, e.g., pens, paper clips and the like, accidentally short-circuiting the contacts of the receptacle and thus causing damage to the interface circuitry inside the computer. Also, removal of the computer&#39;s cover is often necessary to access memory cards, peripheral cards and other parts of the computer. The electronic receptacle is traditionally mounted on the cover and a fly-wire connects the receptacle to the interface circuitry within the computer. The fly-wire enables partial removal of the cover from the computer housing without disconnection of the receptacle. However, the fly-wire can be easily severed and tethering the receptacle to the computer in this fashion is both unwieldy and inconvenient. 
     Consequently, there is a need for an apparatus that protects the ground and signal contacts of an electronic button receptacle from being inadvertently short-circuited by contact with foreign objects. 
     There is a further need for an apparatus that permits an electronic receptacle to be mounted on a removable cover, e.g., bezel, of an electronic housing without requiring a wired electrical connection between the receptacle and interface circuitry of the housing, thereby facilitating removal and replacement of the cover relative to the housing. 
     SUMMARY OF THE INVENTION 
     The present invention, accordingly, provides an apparatus for mounting an electronic button receptacle to a removable cover of an electronic housing that overcomes or reduces disadvantages and limitations associated with prior electronic button receptacle systems. 
     The electronic button receptacle comprises a column moveable within a structure defining a channel having first and second ends, the column includes an electrically conductive contact engageable by a first device at the first channel end. An electrical terminal is spaced from the column at a second channel end, the electrical terminal being electrically connectable to the second device. A connector is electrically connected to the contact and extends within the channel toward the terminal, such that upon engagement of the contact by the first device, the connector electrically engages the terminal, thereby completing the electrical circuit between the devices. 
     A second electrically conductive contact may be located within the channel adjacent the column which is engageable by the first device. A second terminal is spaced from the column at the second channel end, the second terminal being electrically connectable to the second device and also being connectable to the second electrically conductive contact by ground spring means. 
     In another embodiment a housing is used which has cooperating first and second components, the first component having a channel defined therein. A column is moveable within the channel and the column has a first engageable electrically conductive contact. A first electrical pad is secured to the second component proximate the channel, and a first electrical connector electrically connected to the first contact extends within the channel toward the pad, wherein upon engagement of the column, the connector electrically engages the pad. 
     The invention results in several technical advantages. Generally, the first contact does not connect to an electrical signal until the column has been moved within the channel, minimizing the risk of inadvertent short circuits. Further, by using electrical connectors to connect the contacts to their associated electrical pads allows the first and second components of the housing to be easily removed. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1A is a perspective view of an electronic button secured to a substrate such as an employee badge. 
     FIG. 1B is a perspective view of a computer housing with an electronic button receptacle of the present invention mounted within the front bezel of the housing. 
     FIG. 2A is a schematic diagram of the electronic button receptacle of FIG. 1B showing the front bezel attached to the computer housing. 
     FIG. 2B is a schematic diagram of the electronic button receptacle of FIG. 1B showing the front bezel detached from the computer housing. 
     FIG. 3 is an enlarged, cut-away, front perspective view of the electronic button receptacle and a portion of the computer housing of FIG. 1B. 
     FIG. 4 is a cut away, exploded rear perspective view of the electronic button receptacle and a portion of the computer housing of FIG. 3. 
     FIG. 5 is an enlarged, cut-away, rear perspective view of the electronic button receptacle and a portion of the computer housing of FIG. 3. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In FIG. 1A the reference numeral 10 refers to an electronic button. The button 10 comprises a cylindrical metal container having interfitting &#34;female&#34; and &#34;male&#34; members 12 and 14, respectively. The female member 12 operates as an electrical ground terminal and the male member 14 operates as an electrical signal terminal for a semiconductor chip (not shown), located within the button 10. As explained below, the semiconductor chip in the button 10 is used for sending data to, or receiving data from, some type of interface circuitry (not shown). For convenience, the button 10 is secured to a substrate 16, such as an employee badge, ring, key chain or the like. 
     Referring also to FIG. 1B, the button 10 is designed to engage a receptacle 18 electrically connected to an interface circuit (FIG. 2), so that signal data may be transferred between the semiconductor chip of the button 10 and the interface circuit for performing one or more predefined tasks, e.g., authorizing access to a computer 20. The computer 20 housing includes a chassis 22 that contains the interface circuit and a substantially L-shaped, removable cover 24 to which the receptacle 18 is mounted in a front bezel-portion thereof. As will be described subsequently in detail, the receptacle 18 is electrically connected to the interface circuit within the chassis 22, the connection being made without wires extending between the cover 24 and the chassis so that the cover may be freely removed from, and replaced onto, the chassis. 
     FIGS. 2A and 2B illustrate schematically the electrical connections between an interface circuit 26 within the chassis 22 and the receptacle 18. While not shown, it is understood the interface circuit 26 is connected to an appropriate power source and other circuitry as necessary within the chassis 22. It is understood that a generally circular aperture 24a is defined in the cover 24 as part of the receptacle 18 for receiving the button 10. A ground contact 28 (in the form of a circular collar in the illustrated embodiment) is supported in the periphery of the aperture 24a. A ground terminal 30 is electrically connected by a conductive element 32 to the ground contact 28. A signal contact 34, having a switch element 34a connected thereto, is supported by a column or other type of support structure (not shown) in the center of the aperture 24a. 
     Supported in a front wall 22a of the chassis 22 is a ground terminal 36 and a signal terminal 38. Conductive elements 40, 42 electrically connect, respectively, the ground terminal 36 to electrical ground and the signal terminal 38 to the interface circuit 26. 
     In operation, when the cover 24 is in its closed position over the chassis 22 (FIG. 2A), the terminals 36, 38 of the chassis are in alignment, respectively, with the ground terminal 30 and the switch element 34a of the cover. The ground terminal 30 of the cover 24 makes contact with the ground terminal 36 of the chassis 22 forming an electrical connection therebetween. When the button 10 is not yet received in the receptacle 18, the signal contact 34 remains un-depressed and thus the switch element 34a is in an open position, so that no electrical circuit can be completed through the signal contact 34 with the signal terminal 38 in the chassis 22. This prevents an accidental short circuit between the signal contact 34 and the ground contact 28, which might otherwise be caused by a conductive foreign object touching these contacts on the front of the receptacle 18. 
     When the button 10 is received in the receptacle 18, the female member 12 thereof makes electrical contact with the ground contact 28. The male member 14 of the button 10 depresses the signal contact 34, forcing the switch element 34a from its open position to a closed position. In the closed position, the switch element 34a makes electrical contact with the signal terminal 38 of the chassis 22, thereby completing the electrical circuit with the interface circuit 26. Specifically, the semiconductor chip (not shown) within the button 10 is electrically connected to the interface circuit 26 for transfer of data therebetween. When the button 10 is removed from the receptacle 18, the signal contact releases to its un-depressed position and the switch element 34a releases to an open position, wherein there is no longer electrical contact with the signal terminal 38 of the chassis 22. 
     FIG. 2B shows the cover 24 in an open position relative to the chassis 22. In the open position, the ground and signal terminals 36, 38 of the chassis 22 are no longer in electrical contact with the respective ground terminal 30 and switch element 34a. The cover 24 may be removed without breaking any hardwired connections between the cover 24 and the chassis 22. When the cover 24 is replaced to its closed position relative to the chassis, the above-described connections are re-established so that when the button 10 is received in the receptacle 18, an electrical circuit is completed between the button and the interface circuit 26. 
     In FIGS. 3-5 a receptacle 18&#39; is illustrated that represents one embodiment of the receptacle 18 for structurally supporting components thereof within the chassis 22 and the cover 24 of the computer 20. 
     Referring to FIG. 3, a printed circuit board 44 of the receptacle 18&#39; is secured in a suitable fashion (not shown) to the front wall 22a of the chassis 22. A conductive signal pad 44b and a conductive ground pad 44a circumscribing the signal pad 44b, are etched into the board 40 or are otherwise secured thereto. While not shown, it is understood the pads 44b, 44a are connected by conductive elements to the interface circuit 26 (FIGS. 2A, 2B) and electrical ground, respectively. It is further understood the pads 44b, 44a correspond in function to the signal terminal 38 and the ground terminal 36, respectively, mounted to the front wall 22a and described previously with respect to FIGS. 2A, 2B. Moreover, it is contemplated that the interface circuit 26 (FIGS. 2A, 2B) may reside on the board 44, which is then electrically connected to other portions of the computer 20, such as a central processing unit (not shown). 
     Referring also to FIGS. 4-5, components of the receptacle 18&#39; comprising part of the cover 24 include a pedestal 46 secured to a back of the cover over the aperture 24a. The pedestal 46 may be molded into the cover 24 as shown, or may be attached to the cover in any known manner. The pedestal 46 has an open, cylindrical body that defines three posts or stands 46a, 46b and 46c about its outer circumference. The stands 46a, 46b and 46c each define a slot 46d, 46e and 46f, respectively, for reasons to be described below. An end, or floor 46g, of the pedestal 46 defines a circular aperture 46h in the center of the floor, for reasons to be described. 
     A cylindrical column 48 is received in the cylindrical body of the pedestal 46 from an outer side of the cover 24 through the aperture 24a. As described further below, the column 48 is configured to slide back and forth within the cylindrical body of the pedestal 46 and a spring 50 loads the column in an extended position so that a face 48a of the column is normally even with the surface of the cover 24 around the aperture 24a. The column 48 defines a cylindrical wall 48b. A hole 48c, located within the center of the face 48a, extends through a shaft 48d secured to the back side of the face. The shaft 48d may be molded into the column 48 as shown, or attached in any known manner. The shaft 48d is sized to pass through the circular aperture 46h of the pedestal floor 46g, for a use to be described. Three legs 48e, 48f and 48g extend from the cylindrical wall 48b along a central axis of the column 48. Snap tabs 48h, 48i and 48j are located at the ends of each of the legs 48e, 48f, 48g, respectively. The legs 48e, 48f and 48g are sized and located on the column 48 to pass through the slots 46d, 46e and 46f, respectively, in the pedestal 46 as best shown in FIG. 5. Further, the snap tabs 48h, 48i and 48j of the column 48 are designed to pass through slots 46d, 46e and 46f, respectively, and to engage the pedestal stands 46a-46c to restrict the column&#39;s removal from the pedestal 46. The snap tabs 48h, 48i and 48j allow the spring 50 to bias the column 48 at a distance in full extension that is exactly flush with the surface of the cover 24, as shown in FIG. 3. 
     The spring 50 is placed around the shaft 48d of the column 48 and contacts the back of column face 48a and the pedestal floor 46g. As explained further below, when the button 10 engages the face 48a and is received into the aperture 24a, the column 48 slides against the force of the spring 50 into pedestal 46. 
     A signal spring 52 extends into the hole 48c and through the shaft 48d of the column 48. A head 52a of the spring 52 serves as an electrical signal contact for the male member 14 of the button 10. It is understood the spring 52 serves the same function as the signal terminal 34 and switch element 34a of the receptacle 18 described previously with reference to FIGS. 2A, 2B. 
     As shown in FIGS. 3 and 5, the head 52a is secured to the cylindrical column 48 such that the head 52a is flush with the column face 48a proximate the column hole 48c, with the spring 52 passing through the column shaft 48d. As described further below, when the column 48 is depressed within the pedestal 46 by the button 10, the spring 52 engages the signal pad 44b, thereby completing the electrical circuit between the button and the interface circuit 26. 
     Referring to FIG. 4, a substantially circular ground plate 54 fits over and is secured to the pedestal 46 on the rear side of the cover 24. The plate 54 defines tabs 54a and 54b extending therefrom. A square aperture 54c is defined within the tab 54a and a round aperture 54d is defined within tab 54b. The square aperture 54c and the round aperture 54d are used to locate and secure the ground plate 54 to the back of the cover 24 proximate the aperture 24a. Extending from the front center of the ground plate 54 are a plurality of fingers 54e, or electrical contacts. It is understood the fingers 54e serve the same function as the ground contact 28 in the receptacle 18, as described previously with reference to FIGS. 2A, 2B. 
     The fingers 54e define a circular opening 54f in the center of the ground plate 54. Three notches 54g, 54h and 54i are defined in the ground plate 54 around the opening 54f such that the ground plate 54 may be inserted over the pedestal 46 and placed flush with the back of the cover 24. The notches 54g, 54h and 54i are located and sized to allow the stands 46a, 46b and 46c, respectively, to pass through the ground plate 54. When the ground plate 54 is placed flush with the back of the cover 24, the fingers 54e extend between the edge of aperture 24a in the cover 24 and the wall 48b of column 48 so that the fingers 54e can serve as an electrical ground contact for engaging the female member 12 of the button 10, when the button is inserted in the aperture 24a. 
     A circular wall 54j circumscribes and defines the periphery of the ground plate 54. A lip 54k is defined around the end of the wall 54j. The lip 54k is designed to receive and secure, in an electrically conductive manner, one end of a ground spring 56. It is understood that the ground spring 56 performs the same function as the ground terminal 30 of the receptacle 18 described previously with respect to FIGS. 2A, 2B. The ground spring 56 is aligned with, and is biased against, the ground pad 44a on the board 44 for electrical connection therewith. Compression of the ground spring 56 between the ground plate 54 and the board 44 ensures a good electrical connection between the spring and the ground pad 44a. 
     A square peg 58 and a round peg 60 extending from the rear side of the cover 24 secure the ground plate 54 and hence the ground spring 56 to the rear of the cover proximate the aperture 24a. The square peg 58 and round peg 60 are constructed to fit within the square aperture 54c and round aperture 54d, respectively, of the ground plate 54. After the square peg 58 has been inserted into the square aperture 54c, and the round peg 60 has been inserted into the round aperture 54d, such that the ground plate 54 is flush with the rear of the cover 24, both the pegs 58, 60 may be bent or melted over ground plate 54 to secure the ground plate to the cover. By utilizing the square peg 58--round peg 60 combination, the ground plate 54 may only be inserted onto the back of the cover 24 in the proper orientation. 
     In operation, the receptacle 18&#39; operates in a manner similar to that described with reference to the receptacle 18 of FIGS. 2A, 2B. When the cover 24 is in its closed position relative to the chassis 22, the ground spring 56 of the cover 24 is in electrical contact with the ground pad 44a of the board 44. The signal spring 52 is aligned with the ground pad 44b, but is not in electrical contact with it because the column 48 has not been compressed by the button 10. 
     Before the button 10 is received in the aperture 24a, the column face 48a is flush with the front surface of the cover 24 because the column 48 is biased by the spring 50 outwardly from the cover, to the limits of the tabs 48h, 48i, 48j engaging the pedestal slots 46d, 46e, 46f. The signal spring 52 extends within the column shaft 48d, but does not make contact with the signal pad 44a, so there accordingly is no completion of an electrical circuit with the interface circuit 26. Thus any foreign objects creating a conductive contact between the signal spring head 52a and the legs 54e of the ground plate 54 cannot cause a short circuit of the interface circuit 26. 
     When the button 10 is inserted in the aperture 24a, the male member 14 thereof engages the column face 48a and makes electrical contact with the signal spring head 52a. As the button 10 is depressed, the column 48 slides within the body of the pedestal 46 into the cover 24, guided by the legs 48e, 48f, 48g, to the limit of the floor 46g. The female member 12 of the button 10 engages and makes electrical contact with the ground plate fingers 54e. An electrical connection to ground is thus completed between the semiconductor chip (not shown) within the button 10, the female member 12, the fingers 54e, the ground spring 56, the ground pad 44a, and electrical ground. 
     Further, as the button 10 is depressed, the signal spring 52 supported within the column shaft 48d engages the signal pad 44b of the board 44. An electrical signal connection is thus made between the semiconductor chip (not shown) within the button 10, the male member 14, the signal spring 52, the signal pad 44b, and the interface circuit 26. As the button 10 is depressed against the force of the spring 50 to the limit of the floor 46g and then released slightly against the force of the spring 50, it is possible that the electrical connection will be a momentary connection. A momentary connection in some embodiments is sufficient to perform the data transfer operation between the button 10 and the interface circuit 26, although a non-momentary connection is also possible and contemplated by the present invention. The button 10 may remain in the aperture 24a or be removed. 
     The cover 24 may be removed from the chassis 22 and then later replaced, wherein the electrical connections of the receptacle 18&#39; between the cover and the chassis are then reestablished. When the cover 24 is removed from the chassis 22, the ground spring 56 disengages its contact with the ground pad 44b and the signal spring 52 is no longer in alignment with the signal pad 44a. The cover may be completely disassociated from the chassis because there are no wires interconnecting them. The cover 24 may then be replaced to its closed position relative to the chassis 22, whereupon the ground spring 56 engages, and becomes biased against, the ground pad 44b and whereupon the signal spring 52 is in alignment with the signal pad 44a, for possible activation by depressing the button 10 into the aperture 24a, as described above. 
     Several advantages result from use of the present invention. In the manufacture and assembly of the computer 20 a significant degree of variation exists in chassis 22 and cover 24 construction, particularly with regard to the distance of separation therebetween when the cover 24 is closed. The use of signal spring 52 and ground spring 56 to contact the pads 44b, 44a, respectively, thus allow for this variation in separation. Accordingly, the receptacle of the present invention enables existing computer housing manufacturing techniques to be used successfully in a computer equipped with electronic button capabilities. Further, the use of the signal spring 52 and ground spring 56 to create the electrical connection with the board 44 removes the need for a fly-wire to connect the receptacle to the interface circuit, enabling the cover 24 to be easily removed from the chassis 22. Also, because the signal spring 52 is not constantly in contact with the signal pad 44a, the risk of inadvertent contact external contacts with the receptacle causing short circuits is minimized. 
     Additionally, since the ground spring 56 is in contact with the ground pad 44b when the cover 24 is secured to the chassis 22, the ground pad 44b could be used to indicate when the cover 24 has been removed from the chassis 22 by sensing when the ground spring 56 disengages the ground pad 44b. This could be accomplished by utilizing a pressure sensitive ground pad 44b, by forming an electrical circuit through the ground spring 56 and the ground pad 44b, or any other appropriate method. 
     Although an illustrative embodiment of the invention has been shown and described, other modifications, changes, and substitutions are intended in the foregoing disclosure. For example, the electronic button receptacle need not be placed in a computer 20 but could be placed in any other enclosure. The pedestal 46 could have any shape with any number of stands and the column 48 could have any number of legs. The shaft 48d in the column need not pass through the aperture 46h. The signal pad 44a and ground pad 44b need not be circular or arranged one within the other. The signal spring 52 and ground spring 56 may be of any shape as long as they allow connection to associated signal and ground connections. The ground plate could take on any shape as long as the female member 12 of the electronic button 10 contacts an electrical ground when inserted in the electronic button receptacle. Similarly, the signal spring 52 could take on any shape or be located in any position as long as the male member 14 of the electronic button 10 contacts a signal connection when inserted in the electronic button receptacle. 
     Further, in certain applications there may be no need to separate components of the receptacle between the cover 24 and the chassis 22. Accordingly, the pedestal could be directly connected to the printed circuit board, or other electrical device with a signal pad, and the ground plate could be directly wired to ground. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the invention.