OUTPUT TAPPING UNIT FOR USE WITH ELECTRIC DISTRIBUTION TRACKS

• US 3,757,063 A
• Filed: 08/03/1972
• Issued: 09/04/1973
• Est. Priority Date: 10/18/1971
• Status: Expired due to Term

• Current Assignee: Derek James Hart, Robert B. Davis, Wilhelm Henry Valentine Sanhen
• Original Assignee: Derek James Hart, Robert B. Davis, Wilhelm Henry Valentine Sanhen
• Inventors: Davis, Robert, Hart, Derek James, Sanhen, Wilhelm Henry Valentine
• Primary Examiner(s): Smith, Jr., David
• Application Number:
  US05/277,753
• Time in Patent Office: 397 Days
• Field of Search: 339/21R,22B 200/51.07,51.08,5B,51R
• US Class Current: 200/51.07
• CPC Class Codes: H01R 25/142 Their counterparts

Abstract

An electrical fitting enabling power to be tapped from an electric distribution trunking has movable contacts carried by rockers which move, following a scissor action, to set the contacts to on and off positions. The fitting has a rotatable clamp to allow the fitting to be secured to the trunking and has an interlocking arrangement effective between the clamp and the rockers to ensure: 1. THAT THE CLAMP CANNOT BE RELEASED WHEN THE CONTACTS ARE SET TO THEIR ON POSITIONS; AND 2. THAT THE CONTACTS ARE PREVENTED FROM BEING SET TO THEIR ON POSITIONS WHEN THE CLAMP IS RELEASED.

Claims

1. An output tapping unit for use with electric distribution tracks having bare, spaced-apart track conductors, the unit comprising:

a housing, clamping means within said housing, said clamping means including a rotatably-mounted member having ears for releasably engaging ledges provided in an associated electric distribution track to clamp the unit thereto;

said rotatably-mounted member further including a cam portion;

said housing being slotted to permit said ears to emerge from, and to retract into, said housing upon clamping and releasing rotation of said housing;

a switchable contact assembly within said housing, said contact assembly including;

two contact elements mounted in said housing for switchable movement between on and off positions wherein said contact elements are able to make contact with the conductors and of a distribution track in their on position, and movable interlocking means comprising a cam follower co-operable with said cam portion to effect reciprocable movement of said cam follower towards and away from said contact assembly to prevent release of said clamping means from said track when said contact elements are in their on positions.

2. A unit according to claim 1, wherein said contact assembly further includes a pair of pivoted rocker elements which carry said two contact elements, said rocker elements being operable to move said elements inwardly and outwardly to their off and on positions respectively.

3. A unit according to claim 2, wherein said rocker elements are mounted on a common pivot intermediate their ends, and said contact elements are carried on adjacent ends of said rocker elements, exteriorly-operable rotatable camming means being provided to effect movement of said rocker elements, said camming means being located between said rocker elements on the opposite side of said common pivot from said contact elements.

4. A unit according to claim 1 wherein said rotatably-mounted member has a disc portion whose periphery projects out of said slotted housing to enable said member to manipulated.

5. A unit according to claim 1, wherein said cam follower is retracted and spaced from said contact assembly when said clamping member is in its clamping position, said cam follower being capable of moving into abutment against said contact assembly in the on condition thereof when advanced by said cam portion during an initial releasing rotation of said clamping member thereby preventing further releasing rotation of said clamping member, said cam follower and contact assembly being adapted to permit free advancing movement of said cam follower when said contact assembly is in the off condition.

6. A unit according to claim 2, wherein said cam follower is a generally U-shaped yoke having two spaced fingers, the tips of which are located close to the rocker elements of said contact assembly when said clamping member is in its clamping position, said yoke being movable by said cam portion towards said rocker elements in response to an initial releasing rotation of said clamping member and the fingertips of said yoke being located to abut against said rocker elements, when these are in theIr on positions, thereby to react against said cam portion and prevent further releasing rotation of said clamping member.

7. A unit according to claim 3, when the spacing between said fingers is sufficient to allow said fingers to clear said rocker elements when the latter are in their off positions, thereby permitting unimpeded advance movement of said yoke and providing corresponding freedom of rotation of said clamping member to its release position.

8. A unit according to claim 6, wherein while said fingers are fully advanced, corresponding to the release position of said clamping member, said fingers are located on either side of said rocker elements, thereby preventing operation of said rocker elements to set the contact elements to their on positions.

9. A unit according to claim 5, wherein said cam portion is of generally elliptical shape, its major axis lying across said housing when said clamping member is in its clamping position, said major axis being aligned along said housing with said cam follower fully advanced when said clamping member is moved to its releasing position.

10. A unit according to claim 9, wherein spring means are provided to bias said cam follower against said cam portion.