Captive screw with deployable knob

{
  "publication_number": "US7241096B2",
  "country": "US",
  "kind": "B2",
  "title": "Captive screw with deployable knob",
  "abstract": "A captive screw for use in electronic assemblies includes a screw with a shaft having a pair of spaced grooves and a cover captivating the screw and for attaching the captive screw. A knob for rotating the screw can be moved along the shaft between an extended position and a lowered position corresponding to the grooves on the shaft, and releasably locked to the shaft in either position. A lock wafer is used to secure the knob to the shaft. A release button with a large head actuates the lock wafer.",
  "claims": [
    "1. A captive screw with a deployable knob for electronic assemblies, the captive screw comprising: (a) a screw having a shaft with first end, and a threaded end for engaging a first panel, and at least two, spaced, grooves formed in the shaft; (b) a cover captivating the screw and for attaching the captive screw to a second panel; (c) a knob assembly rotationally fixed to the shaft and movable along the shaft, the knob assembly being positioned proximate the first end of the shaft; the knob assembly being movable between a first position and a second position and including: (1) a knob having a core cavity; and (2) a lock wafer movable in the knob between a locked position and an unlocked position for engaging either one of the grooves formed in the shaft in the locked position, the knob assembly being movable along the shaft when the lock wafer is in the unlocked position, the screw and knob assembly being fixed to rotate as a unit; and (3) a clutch for moving the lock wafer between the locked position and the unlocked position, the clutch including: (A) a release button having a head and being movable between a locked position and an unlocked position; and (B) a spring for biasing the release button in the locked position; the knob having the core cavity with an upper section and a lower section, the lower section being adapted for receiving the screw, the upper section having a cross-sectional area substantially coextensive with the cross-sectional area of the knob, the upper section of the core cavity being adapted for receiving the head of the release button, the head of the release button being substantially coextensive with the cross-sectional area of the upper section of the core cavity and centered in the upper core cavity.",
    "2. A captive screw according to claim 1, wherein the release button head provides an operator with a large contact surface for actuating the knob assembly, thus reducing the likelihood of accidental actuation of the captive screw.",
    "3. A captive screw according to claim 1 wherein the screw has a head adapted to receive a driver, the head of the release button having an aperture formed therein to provide operation of the screw head with a driver.",
    "4. A captive screw according to claim 1 wherein the head of the release button is generally circular.",
    "5. A captive screw according to claim 1, the knob assembly further including a spring for biasing the lock wafer in the locked position.",
    "6. A captive screw according to claim 1, the release button being movable in a first direction, the lock wafer being moveable in a second direction, the first direction being perpendicular to the second direction.",
    "7. A captive screw according to claim 1, the release button having a camming surface for moving the lock wafer.",
    "8. An electronic device including a chassis and at least one removable assembly including electronic components, the at least one assembly including a captive screw with a deployable knob, the captive screw comprising: (a) a screw having a shaft with a threaded end for engaging a first panel and at least two, spaced, grooves formed in the shaft; (b) a cover captivating the screw and for attaching the captive screw to a second panel; (c) a knob assembly rotationally fixed to the shaft and movable along the shaft, the knob assembly being positioned proximate the first end of the shaft; the knob assembly being movable between a first position and a second position and including: (1) a knob having a core cavity; and (2) a lock wafer movable in the knob between a locked position and an unlocked position for engaging either one of the grooves formed in the shaft in the locked position, the knob assembly being movable along the shaft when the lock wafer is in the unlocked position, the screw and knob assembly being fixed to rotate as a unit; and (3) a clutch for moving the lock wafer between the locked position and the unlocked position, the clutch including: (A) a release button having a head and being movable between a locked position and an unlocked position; and (B) a spring for biasing the release button in the locked position; the knob having the core cavity with an upper section and a lower section, the lower section being adapted for receiving the screw, the upper section having a cross-sectional area substantially coextensive with the cross-sectional area of the knob, the upper section of the core cavity being adapted for receiving the head of the release button, the head of the release button being substantially coextensive with the cross-sectional area of the upper section of the core cavity and centered in the upper core cavity.",
    "9. An electronic device according to claim 8, wherein the release button head provides an operator with a large contact surface for actuating the knob assembly, thus reducing the likelihood of accidental actuation of the captive screw.",
    "10. An electronic device according to claim 8 wherein the screw has a head adapted to receive a driver, the head of the release button having an aperture formed therein to provide operation of the screw head with a driver.",
    "11. An electronic device according to claim 8 wherein the head of the release button is generally circular.",
    "12. An electronic device according to claim 8, the knob assembly further including a spring for biasing the lock wafer in the locked position.",
    "13. An electronic device according to claim 8, the release button between movable in a first direction, the lock wafer being moveable in a second direction, the first direction being perpendicular to the second direction.",
    "14. An electronic device according to claim 8, the release button having a camming surface for moving the lock wafer."
  ],
  "description_excerpt": "1. Field of the Invention The present invention relates generally to fasteners for electronic equipment. 2. Brief Description of the Prior Art Captive screws are fasteners that include a screw portion which is “captivated” or held by a ferrule or like structure that in turn can be attached to a first panel. The screw portion is captivated so that it can be moved with respect to the first panel and the screw's threads can engage a corresponding aperture in a second panel, so that the first and second panels can be secured together. However, when the panels are unscrewed and disengaged, the screw is retained in the first panel. Captive screws are useful in applications where it is important to avoid dropping or losing screws during assembly or repair, such as for electronic devices, where a lost screw can cause catastrophic electrical shorts damaging equipment. There is a need for an improved captive screw for use in securely attaching removable electronic assemblies, such as PCI card riser cages, to electronic chassis such as rack-mountable computer chassis.\n\nThe present invention provides an improved captive screw for use in electronic assemblies, and in particular for use in releasably securing assemblies such as PCI board riser cages to computer chassis, such server chassis. The captive screw of the present invention is of the type that includes a screw having a shaft with a first end and a threaded end for engaging a first panel. The shaft also has at least two, spaced grooves formed in the shaft. The captive screw further includes a cover captivating the screw and for attaching the captive screw to a second panel.",
  "cpc": [
    "F16B 37/14",
    "F16B 21/18",
    "Y10S 411/999"
  ],
  "ipc": [
    "F16B 21/18"
  ],
  "assignees": [
    "SOUTHCO"
  ],
  "inventors": [
    "SMITH KELLY K",
    "RODRIGUEZ ISMAEL",
    "CLOAREC LOIC J",
    "THOMPSON DANIEL T"
  ],
  "filing_date": "2005-06-24",
  "publication_date": "2007-07-10",
  "grant_date": "2007-07-10",
  "priority_date": "2005-06-24",
  "application_number": "US-16047205-A",
  "family_id": "37567586",
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}