Patent Application
20150131209
The present invention relates to high-power electrical switches, and in particular to a flexible cable assembly for remotely actuating electrical switches such as circuit breakers.
High-power electrical circuitry is normally placed inside a metal cabinet to protect the electrical circuitry from the external environment and to shield users from potential hazards associated with the operation of the circuitry.
Often the cabinet provides a handle that serves both to lock a cabinet door and to disconnect electrical power from the interior circuitry before the door is opened. The handle may communicate through a flexible cable assembly with a switch inside the cabinet, for example, a circuit breaker, so that when the handle is moved to allow opening of the cabinet door, the circuit breaker is also opened, removing electrical power from the interior circuitry. This feature is normally subject to the mechanical override in the event that the cabinet must be operated with the door open and the circuitry live.
A flexible cable assembly provides a substantially incompressible sheath through which a flexible cable may slide. Opposite ends of the sheath are fixed, respectively, to a stationary structure of the handle and an actuator frame attached to the circuit breaker housing. One end of the flexible cable is then attached to a movable portion of the handle to communicate this motion through the flexible cable to a slider held within the actuator frame. The slider may provide a collar capturing a toggle operator of the circuit breaker to move the circuit breaker toggle between an “on” and “of” position with movement of the flexible cable by the handle.
When it is necessary to work on equipment controlled by the circuitry within the cabinet, it is known to move the handle to the “off” position thereby disconnecting electrical power to the interior circuitry as described above. The handle normally provides a locking feature allowing insertion of a padlock or the like through portions of the handle preventing the handle from being moved from the “off” position to the “on” position. While the electrical power is thereby removed from the interior circuitry, this state of the handle allows opening of the cabinet door such as may allow access to the interior circuitry. Such access could allow inadvertent reactivation of the circuit breaker, for example, by damage or disconnection of the flexible cable, risking unexpected machine activation.
The present invention provides a remote actuator system that allows a lock such as a padlock to be placed directly on the actuator frame on the electrical switch to prevent switching of the associated electrical switch. By employing the collar and slider system of the actuator a direct locking of the electrical switch may be provided even when features for locking are not included in the lock itself.
In one embodiment, the invention provides a remote switching assembly for use with an electrical switch having a switch operator movable along an actuation axis which includes an actuator flame presenting a longitudinal channel extending along a longitudinal axis and attachment elements for attaching the actuator frame to a housing of an electrical switch adjacent to the switch operator so that the longitudinal axis is substantially parallel to the actuation axis. A slider fitting within the longitudinal channel of the actuator frame may slide along the longitudinal axis and may provide a collar receiving the switch operator when the actuator frame is fixed to the housing of the electrical switch, so that movement of the slider along the actuation axis may switch the switch operator between “on” and “off” states. A flexible cable assembly provides a sheath surrounding a flexible cable, the first end of the sheath attached to the actuator frame and a first end of the flexible cable attached to the slider. The actuator frame provides at least one opening through the channel for receiving a lock shank to extend into the channel to block motion of the slider along the actuation axis to switch the switch operator from the “off” state to the “on” state.
It is thus a feature of at least one embodiment of the invention to provide an ability to locally lock an electrical switch for extra assurance that the switch remains in an “off” state.
The actuator frame may provide two opposed openings on opposite walls of the channel so that the lock shank may extend fully across the channel.
It is thus a feature of at least one embodiment of the invention to fully block the channel to prevent ready defeat of the lock.
One opening may also provides passage of the collar of the slider out of the channel for motion of the slider along the actuation axis between the “off” state and the “on” state.
It is thus a feature of at least one embodiment of the invention to provide a lockout system that works with the large opening for the slider collar allowing simplified installation of the lock in awkward working environments.
The slider may include a third opening aligning with the two opposed openings through the channel when the slider is in the “off” state to receive the lock shank.
It is thus a feature of at least one embodiment of the invention to positively lock the slider within the channel.
The third opening may be an upwardly opening slot extending perpendicularly to the actuation axis.
It is thus a feature of at least one embodiment of the invention to allow simple injection molding of the slider.
The attachment elements may be flange portions of the actuator frame having holes for receiving machine screws to attach the actuator frame to the electrical switch.
It is thus a feature of at least one embodiment of the invention to prevent rapid defeat of the lockout by requiring removal of multiple machine screws yet allowing removal when necessary.
The remote switching assembly may include a cover fitting over the channel in the channel element of the actuator frame and the openings may be located to permit installation of the cover without interference from the lock shank.
It is thus a feature of at least one embodiment of the invention to permit the lock to be used without disassembly of the cover.
The cover may be attached to the actuator frame by inter-engaging hook elements engaged by sliding of the cover and retained by a snap detent.
It is thus a feature of at least one embodiment of the invention to provide security against tampering with the slide when the cover is readily removable.
The actuator frame and the slider may be injection molded thermoplastic.
It is thus a feature of at least one embodiment of the invention to increase the resistance of the actuator assembly to tampering when constructed of thermoplastic material.
The sheath and the flexible cable of the flexible cable assembly may be connected to the actuator frame and the slide by means of keyway slots slidably engaging flange features on the sheath and flexible cable.
It is thus a feature of at least one embodiment of the invention to provide security against defeat of the actuator by removal of the cable by positively locking the slider.
The remote switching assembly may further include a handle mechanism that is mountable to a cabinet surface having a handle frame and a handle movable with respect to the handle frame between a first position and a second position and wherein a second end of the sheath is attached the handle frame and a second end of the flexible cable is attached to the handle so that movement of the handle between the first position and second position move the slider in a range sufficient to switch the switch operator between the “on” and “off” states.
It is thus a feature of at least one embodiment of the invention to provide robust lockout against remote actuation of the electrical switch.
The handle mechanism further includes an opening for receiving a lock shank for preventing movement of the handle from an off position in which the switch operator is in the “off” state to an on position.
It is thus a feature of at least one embodiment of the invention to provide a robust lockout against actuation of the electrical switch by damage or removal of the flexible cable.
The above aspects of the invention are not intended to define the scope of the invention for which purpose claims are provided. In the following description, reference is made to the accompanying drawings, which form a part hereof and in which there is shown by way of illustration, and not limitation, a preferred embodiment of the invention. Such embodiment does not define the scope of the invention and reference must be made therefore to the claims for this purpose.
Reference is hereby made to the following figures in which like reference numerals correspond to like elements throughout, and in which:
Referring now to
The front panel 18 may be fixed to one edge of the cabinet 10 against a left side wall 16 and spanning an upper and lower side wall 16 and may support a handle assembly 24. The handle assembly 24 may include a frame 26 supporting a pivoting handle 28 which may swing between an upper “on” position and a lower “off” position (the latter shown in
Referring also to
Generally, the movable handle 28 controls an actuation linkage 34 attached to a portion of the handle frame 26 inside the cabinet 10. This actuation linkage 34 in turn may be attached to a flexible cable 36 fitting within a tubular cable sheath 38 together forming a flexible cable assembly 40. The end of the sheath at the handle assembly 24 may be fixed by a clamp 41 to the handle frame 26 so that movement of the actuation linkage 34 by the handle 28 slides the flexible cable 36 within the sheath 38.
As is generally understood in the art, the flexible cable 36 and tubular cable sheath 38 may be relatively freely flexed across their axes of extension but are substantially resistant to changes in dimension in tension or compression along their axes of extension to efficiently transmit the relative motion between the flexible cable 36 and the sheath 38 to a remote location. Generally, motion of the handle 28 through its entire range will provide for a relative movement between the flexible cable 36 and the cable sheath 38 of a predefined distance 42 as will be discussed further below. The actuation linkage 34 controls the relationship between the movement of the handle 28 and the desired predefined distance 42 of the flexible cable 36.
Referring again to
Referring now to
The cable assembly 40 may attach to a lower end of the actuator frame 46 (as will be discussed below) so that the flexible cable 36 extending through the sheath 38 may pass into the channel 48 along the actuation axis 50 to attach to the slider 52. As so assembled, movement of the flexible cable 36 will move the slider 52 along the actuation axis 50 within the actuator frame 46.
When the slider 52 is within the channel 48 and the cable assembly 40 attached to the actuator frame 46, an actuator frame cover 58 may be installed to cover the upper opening of the channel 48 and a portion of the cable assembly 40 within that channel 48. With the actuator frame cover 58 in place, the collar 54 remains uncovered, projecting from the side of the actuator frame 46.
A fiducial feature 59 of the slider 52 may project upward through a slot 60 in the actuator frame cover 58 so that the relative position of the slider 52 within the actuator frame 46 may be visually determined through the actuator frame cover 58. Generally, the actuator frame cover 58 may be attached to the actuator frame 46 by sliding engagement between a set of downwardly extending hooks 62 on the actuator frame cover 58 and laterally outwardly extending hooks 64 at an upper edge of the channel 48 of the actuator frame 46, as will be discussed in more detail below.
Referring also to
This inter-engagement of the toggle operator 74 is such as to allow movement of the slider 52 and collar 54 to fully actuate electrical switch 14, moving the toggle operator 74 between an “on” position in which electrical current is conducted through the electrical switch 14 and “off” position in which electrical current is interrupted, when the slider 52 moves by the predefined distance 42.
Each of the slider 52, actuator frame cover 58, and actuator frame 46 may be constructed of injection molded thermoplastic having a high electrical dielectric to resist electrical conduction through these components to the flexible cable 36 should electrical power be applied to any of these components.
Referring now to
The radially projecting circular flange 82 may be substantially cylindrical like a washer and of greater diameter than the diameter of a circle circumscribing the flats of the hex nut 80. For example, the circular flange 82 may have a diameter of 1 inch and an axial thickness of approximately 9/16 of an inch. The lower end of the actuator frame 46 may provide a U-shaped groove 84 of equal diameter to the circular flange 82 that may receive the circular flange 82 while allowing the hex nut 80 to extend outward from the actuator frame 46 to be readily accessible. The U-shaped groove 84 is sized to permit free rotation of the circular flange 82 therein but to substantially resist translation of the circular flange along the actuation axis 50.
It will be appreciated that rotation of the threaded fastener 78 will move the threaded fastener along the threaded ferrule 76 adjusting the relative point of attachment of the sheath 38 to the actuator frame 46 as will be discussed further below. When the actuator frame cover 58 of
Referring still to
Referring now also to
Referring now to
The handle 28 may then be moved to the “on” position and the on extreme point 106 established with respect to the scale 103. The predefined distance 42 will be the distance between the on extreme point 106 and the off extreme point 102. The threaded fastener 78 may then be adjusted to move a center point 108 between the off extreme point 102 and on extreme point 106 to be approximately centered at a center point 110 of the visual scale 104. The tuned assembly is then sent to the user who normally need not adjust the threaded fastener 78 on-site.
The visual scale 104 includes a dead zone 112 about the center point 110 indicating the region where the position of the toggle operator 74 shown in
Referring now to
In that assembly process conducted at the manufacturer, the actuator frame 46 is first attached to the switch 14 as discussed above with respect to
As indicated by process block 122, the threaded fastener 78 may then be assembled onto the threaded ferrule 76 as shown in
At process block 124, the slider 52 may be inserted into the channel 48 so that the collar 54 fits around the toggle operator 74 as shown in
Referring now to
The actuator frame cover 58 may include a downwardly extending lock tab 130 that passes over a locking ramp 132 on an inner vertical wall of the actuator frame 46 near groove 84. As shown in
Referring again to
Referring now to
Alternatively, in a second position 139b, the aperture 138 may be moved to position 134′ so that the shank 136 of the padlock 137 may pass adjacent to an upper wall of the slider 52 to prevent movement of the slider 52 toward the “on” position, yet without requiring slot 140.
As shown in
Referring to
A lower portion of the collar 54 may be expanded in a flange 146 to provide a stabilizing surface that rests against the upper surface of the switch 14 for improved stability. Generally, in the locked position, the machine screws 66 (shown in
Certain terminology is used herein for purposes of reference only, and thus is not intended to be limiting. For example, terms such as “upper”, “lower”, “above”, and “below” refer to directions in the drawings to which reference is made. Terms such as “front”, “back”, “rear”, “bottom” and “side”, describe the orientation of portions of the component within a consistent but arbitrary frame of reference which is made clear by reference to the text and the associated drawings describing the component under discussion. Such terminology may include the words specifically mentioned above, derivatives thereof, and words of similar import. Similarly, the terms “first”, “second” and other such numerical terms referring to structures do not imply a sequence or order unless clearly indicated by the context.
When introducing elements or features of the present disclosure and the exemplary embodiments, the articles “a”, “an”, “the” and “said” are intended to mean that there are one or more of such elements or features. The terms “comprising”, “including” and “having” are intended to be inclusive and mean that there may be additional elements or features other than those specifically noted, it is further to be understood that the method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed.
It is specifically intended that the present invention not be limited to the embodiments and illustrations contained herein and the claims should be understood to include modified forms of those embodiments including portions of the embodiments and combinations of elements of different embodiments as come within the scope of the following claims. All of the publications described herein, including patents and non-patent publications, are hereby incorporated herein by reference in their entireties.
