SWITCH ACTUATING MECHANISM

Abstract: An electrical power distribution switch (12) includes an actuating mechanism (10) which prevents undersirable rapid reversal of the shaft (14) of the switch (12) while permitting reversal of the shaft (14) deliberately without removal of the handle (24) from the shaft (14). The preferred actuating mechanism (10) includes a ratchet (26) having a remotely operable ratchet pin (30) for controlling the ratchet direction.

Description: S ITCH ACTUATING MECHANISM The invention relates generally to an electrical power distribution switch and more particularly to an actuating mechanism for this type of switch. Background of the Invention Power distribution switches which are actuated by rotation of an external operating shaft are well known. See, for example, U.S. Patent No. 4,467,161. Such switches typically have a rocker arm movable between three positions: two closed positions and an intermediate open position. A plurality of contacts are mounted on the rocker arm, and positions of mechanical equilibrium for the shaft and for the rocker arm corresponding to the three switch positions are provided by an operator so that rotation of the external shaft causes snap action movement of the rocker arm from one position to another. It is desirable that such a switch include actuating means which enable reversal of the shaft but prevent rapid reversal thereof, and prevent the switch from accidentally being shifted from one closed position to the other when it is desired to shift the switch from a closed position to the open position. In the past, removable breakaway handles have been used as actuating means. Such a handle is removably attached to the shaft and is capable of applying torque to the shaft in only a single direction. Stops are provided to limit the stroke of the handle so that throwing of the switch from one closed position to the other requires the handle to be removed from the shaft, shifted to a new position, and replaced on the shaft. Reversal of the shaft similarly requires removal, reorientation and replacement of the handle. : Summary of the Invention It is a general object of the invention to provide a novel actuating mechanism for an electrical power distribution switch which prevents undesirable rapid reversal of the operating shaft, while enabling deliberate reversal thereof without removal of the switch handle from the operating shaft. It 'a further object of the invention to provide an actuating mechanism which enables an electrical power distribution switch to be thrown from one position to an adjacent position with a single stroke of the handle, and which enables the switch to be advanced to the next position by further strokes of the handle without removal of the handle from the shaft. Further objects and features of the invention are set forth below. Brief Description of the Drawings FIG. 1 is a diagrammatical view of an electrical power distribution switch in accordance with the invention; FIG. 2 is a side elevational view of the actuating mechanism of the switch of FIG. 1; FIG. 3 is a bottom view of the actuating mechanism of FIG. 2; FIG. 4 is a fragmentary sectional view taken substantially along line 4-4 in FIG. 2, looking in the direction of the arrows; and FIG. 5 is a fragmentary sectional view taken substantially along line 5-5 in FIG. 2, looking in the direction of the arrows. Detailed Description of a Preferred Embodiment The invention is generally embodied in an actuating mechanism 10 for use in an electrical power distribution switch 12 wherein opening and closing of the switch is accomplished by rotation of an external operating shaft 14 connected to a spring-loaded operator 16. * A switch of this type is described and illustrated in more detail in U.S. Patent No. 4,467,161 which is commonly assigned with the present application and incorporated herein by reference. The operator 16 may be of known construction such as that disclosed in U.S. Patent No. 3,403,565, which is commonly assigned with the present application and incorporated herein by reference. The illustrated switch 12 includes a sealed housing 18 containing a dielectric such as oil or a suitable gas. A seal 19 (FIG. 3) prevents leakage of dielectric fluid around the shaft 14. A set of three movable contacts 20a, 20b and 20c is mounted on a rocker arm 22 which is supported for rotation within the housing 18. The rocker arm 22 is rotatable between a first closed position wherein the movable contacts 20a, 20b and 20c engage a first set of fixed contacts 24a, 24b, 24c, a second closed position where the movable contacts engage a second set of fixed contacts, 26a, 26b and 26c, and an open position between the closed positions. One of the closed positions is normally a tie or ground position. To throw the switch 12, a worker rotates the external operating shaft 14. Upon rotation of the shaft 14 to a predetermined point, the operator 16 rotates the rocker arm 22 with a snap action motion from one position to an adjacent position. The ■ operator 16 provides a position of mechanical equilibrium at each of the three switch positions. in accordance with the present invention, the actuating mechanism 10 employs an elongated handle 24 connected to the shaft 14 by a ratchet mechanism 26 which prevents undesirable rapid reversal of the shaft rotation while enabling deliberate reversal thereof without removal of the handle 24 from the shaft 14. The ratchet mechanism 26 also enables the switch 12 to be thrown from one closed position to the other closed positiβn by reciprocated movement of the handle 24, without removal of the handle 24 from the shaft 14.- The actuating mechanism 10 preferably includes remotely operable means 46 for reversing the rachet mechanism 26 as described below. Turning to a more detailed description of the preferred embodiment of the invention, the shaft 14 is fixed to a lock plate 28. The handle 24 is pivotably attached to the external end of the shaft 14 by a bolt 27. A socket 29 on one end of the handle 24 receives the end of the shaft 14. The handle 24 has a movable ratchet pin 30 mounted thereon with a beveled end 32 extendable into apertures 34 in the lock plate 28. The pin 30 is parallel to the shaft 14 and biased toward the lock plate 28 by a coil spring 36 which is compressed between a first washer 40 abutting a surface on the handle 24, and a second washer 42 abutting a transverse key 44 extending through the pin 30. Engagement between the beveled end 32 of the pin 30 and one of the apertures 34 in the lock plate 28 prevents relative rotation between the handle 24 and the shaft 14 in one direction while permitting such relative rotation in the opposite direction. Referring to FIG. 2, rotation of the handle 24 in a counterclockwise direction about the axis of the shaft 14 will result in corresponding counterclockwise rotation of the shaft 14, but clockwise rotation of the handle 24 from the position shown in FIG. 2 will not result in rotation of the shaft 14. To reverse the ratchet, the pin 30 is rotated 180° about its axis. Manipulation of the pin 30 in this manner is facilitated by an elongated direction indicator 46 having a point 48 on one end to indicate the direction of the ratchet and an eye 50 on its opposite end for engagement by a hook or other manipulation means. To prevent undesired rotation of the pin 30, detent means are provided in the form of a slot 51 in the handle 24 for receiving the transverse key 44. During operation, the spring force urges the key 44 into the detent slot 51, thus preventing rotation of the pin 30. The illustrated actuating mechanism 10 is particularly suitable for use on a switch located in an underground vault wherein the switch may be thrown by a worker positioned above the switch with a hookstick. Accordingly, the handle 24 has an eye 52 on its movable end. Positioning of the eye 52 at the end of the handle 24 provides a maximum mechanical advantage. The illustrated actuating mechanism 10 includes switch position indicators 54 attached to the lock plate 28. The position indicator 54 at the top of the switch 12 indicates the position of the switch 12 and will be readable by a worker throwing the switch from above the vault. Shifting of the switch 12 from a particular position to an adjacent position requires a predetermined angular displacement of the rocker arm 22. Such predetermined displacement of the rocker arm 22 is effected by similar angular displacement of the external shaft 14. The spacing of the apertures 34 in the lock plate 28 is substantially identical to the spacing of the three switch positions of the rocker arm 22 and shaft 14. That is, in the preferred embodiment, the open position of the switch 12 is located 60° from each of the closed positions and the apertures 34 in the lock plate 28 are spaced at 60° intervals. The actuating mechanism 10 includes a frame 56 which provides stops 58, 60 for the handle 24 that allow angular displacement of the handle 24 through an arc slightly greater than the spacing of the apertures 34 (and of the switch positions) but less than twice the spacing thereof. The reason for allowing greater than 60° displacement of the handle 24 is that although throwing the switch 12 nominally requires rotation of the shaft 60°, slightly greater rotation of the shaft 14 may be required in practice. When the switch 12 is in an equilibrium position with the pin 30 engaging an aperture 34 and the direction indicator point 48 aiming away from the nearer handle stop 58 or 60, if the handle is pivoted to the nearer stop, the pin 30 is disengaged from the aperture 34 and does not engage any other apertures, nor does it effect similar motion of the lock plate. The handle 24 must be advanced from the stop 58 or 60 in the direction of the indicator point 48 until the pin 30 re-engages the aperture 34 before the lock plate 28 will rotate with the handle. Accordingly, the maximum angular displacement of the lock plate 28 in a single stroke of the handle 24 is less * than the range of motion of the handle between the stops 58, 60. The spacing of the apertures 34 and positioning of the stops 58, 60 as described above cooperate to provide several desirable features. First, the switch 12 may be thrown from the open position to a closed position, or from a closed position to the open position, in a single stroke of the handle 24; but the switch 12 may not be thrown from a closed position to a closed position with a single stroke of the handle 24. Second, the switch 12 may be thrown from a closed position to closed position by three strokes of the handle 24: a first stroke in a first rotational direction; a second stroke in the opposite rotational direction which shifts the ratchet pin 30 from one aperture 34 to an adjacent aperture; and a third stroke in the original direction. Thirdly, displacement of the handle 24 through arcs of less than the spacing of the switch positions does not shift the ratchet pin 30 from one aperture 34 to another, and accordingly the actuating mechanism 10 does not have any positions of mechanical equilibrium between the open and closed switch positions. ; The frame 56 of the actuating mechanism 10 comprises two generally U-shaped members 66, 68 which are fixed to the switch housing 18. The frame 56 includes top and bottom walls 62, 64, each of which has an elongated slot 70 therein for receiving a radially-projecting tab 72 on the lock plate 28 to serve as a stop for the lock plate. It may be desirable to lock the switch in a particular position to prevent tampering by unauthorized persons. To this end, a first set of notches 74 is provided on the periphery of the lock plate at 60° intervals corresponding to each of the three switch positions for engagement by a padlock. A padlock shackle can be passed through the opening 78 and the notch 76 in the bottom wall 64 and one of the notches 74. A second set of notches 80 is also provided on the periphery of the lock plate at intervals corresponding to the three switch positions for engagement with a sliding bolt lock. A sliding bolt lock could be fastened to the side wall 82 of the frame 56 so that its sliding bolt would pass through a circular hole 84 in the side wall 82 for engagement with one of the notches 80 in lock plate 28. From the foregoing it will be appreciated that the present invention provides a novel and improved actuating mechanism for throwing an electrical power distribution switch. While a preferred embodiment is described and illustrated herein, there is no intent to limit the scope of the invention to this or any particular embodiment. The actuating mechanism of the invention could be used in a two-position switch rather than the three-position switch described herein. In other embodiments of the invention, the actuating mechanism might have a different frame and/or a different orientation.

Claims: What is Claimed is: 1. A switch actuating mechanism comprising: a rotatable shaft; an elongated handle connected to said shaft for rotating said shaft; means for permitting motion of said elongated handle in one predetermined direction relative to said shaft while prohibiting motion of said elongated handle in an opposite predetermined direction relative to said shaft; and means for determining said first and second predetermined directions without removal of said handle from said shaft. 2. A switch actuating mechanism comprising: a rotatable shaft; an elongated handle connected to said shaft for rotating said shaft; a ratchet mechanism connected to said handle and to said shaft to convert reciprocated angular displacement of said handle into rotation of said shaft in a single predetermined direction; and remotely operable means for reversing the direction of said ratchet. 3. A mechanism in accordance with claim 2 wherein said means for reversing said ratchet includes means for providing a visual indication of the direction of said ratchet. 4. A mechanism in accordance with claim 2 wherein said ratchet mechanism comprises a rotatable lock plate fixed to said shaft and having a plurality of circumferentially spaced apertures therein, and a spring-biased pin mounted on said handle, said pin having a beveled tip receivable in said apertures. 5. A mechanism in accordance with claim 4 wherein said apertures are spaced at intervals of 60° on said plate. 6. An electric power distribution switch comprising: a sealed housing containing a quantity of dielectric fluid; a rocker arm having a longitudinal axis and being supported for rotation about said longitudinal axis within said housing; three movable contacts mounted on said rocker arm; at least one set of three fixed contacts engageable by said movable contacts; an operator connected to said rocker arm for selectively applying torque thereto; a shaft connected to said operator so that rotation of said shaft to a predetermined position causes said operator to shift the position of said rocker arm from a first position to a second position; handle means connected to said shaft to facilitate rotation thereof; and ratchet means connected to said handle means and to said shaft so that reciprocated angular displacment of said handle through a predetermined arc results in rotation of said shaft in a single predetermined direction. 7. A switch in accordance with claim 6 wherein said operator defines three equilibrium positions for said rocker arm, said positions being spaced at predetermined angular intervals; and wherein said ratchet means includes a ratchet pin and a rotatable plate having a plurality of apertures formed therein at angular intervals substantially identical to said predetermined angular intervals of said equilibrium positions for engagement by said ratchet pin. 8. A switch in accordance with claim 6 further comprising direction selection means for enabling reversal of said ratchet means to change the direction of rotation of said shaft in response to said reciprocated angular displacement of said handle through said predetermined arc. 9. A switch in accordance with claim 8 wherein said direction selection means is remotely operable. 10. A switch actuating mechanism comprising: a rotatable shaft; a handle connected to said shaft; and a ratchet mechanism connected to said shaft and said handle comprising a plate fixed to said shaft and having a plurality of circumferentially spaced apertures therein, a pin mounted on said handle and biased toward said plate, said pin having a beveled end for insertion into said apertures, said pin having a longitudinal axis and being rotatable about said longitudinal axis, said pin having reversal means thereon to enable rotation of said pin about said axis, said reversal means comprising a pointer having an eye thereon for receiving manipulation means. 11. A mechanism in accordance with claim 10 further comprising first and second stops for restricting the rotation of said plate to an arc of about 120°. 12. A mechanism in accordance with claim 10 further comprising means for limiting rotation of said shaft to a first predetermined arc, and means for restricting rotation of said handle to a second predetermined arc, said second predetermined arc being shorter than said first predetermined arc.

Inventors: AKERS DONALD J, SCHAFFER JOHN S, AKERS, DONALD, J., SCHAFFER, JOHN, S.
Applicants: G & W ELECTRIC, G & W ELECTRIC CO.
Application year: 1986
Main classification: H01H21
IPC codes: H01H3