Not Applicable
The present invention relates to electrical disconnects for mounting in cabinets and having a forwardly-extending, rotary shaft that may engage a handle on the cabinet door when the cabinet door is closed, and in particular to an improvement in such a disconnect that reduces the chance of current flowing through the disconnect when the cabinet door is open.
Referring to
Input terminals along the top of fuse block 10 may receive wires 18 which connect independently to one side of each fuse cartridge 12, the latter which interconnect wires 18 to wires 20 attached to output terminals along the bottom of the fuse cartridge 12. Wires 18, for example, may be connected to a source of three-phase power and wires 20, for example, may be connected to a motor or other piece of equipment.
Fuse block 10 may be activated to electrically disconnect wires 18 from the respective fuse cartridges 12. The fuse block 10 may be controlled by a rotary shaft 22 along one side of the fuse block 10 and extending in an orientation perpendicular to the rear wall 14 of cabinet 16 toward an open face of the cabinet.
The open face of the cabinet may be covered by a door 24 attached by hinges to one side of the cabinet 16. Door 24 may support a captively mounted rotary knob 26 having an inwardly extending connector 28.
Referring now to
When door 24 is closed about the cabinet 16, connector 28 of the knob 26 engages the outermost end of rotary shaft 22, thereby allowing rotary shaft 22 to be operated by knob 26 when door 24 is closed on cabinet 16. Specifically, an inwardly facing end of connector 28 may include a keyway 32 receiving a rectangular end of rotary shaft 22 and a pin 34 extending perpendicularly through the rotary operator. Turning knob 26, in turn, rotates shaft 22 to electrically disconnect or connect power to wires 20.
Referring again to
One apparatus for preventing the reconnection of power while the door is open includes bracketing that is connected to the exterior of fuse block 10. The bracketing enables knob rotation to connect and disconnect the power when the door is closed, and further prevents inadvertent counter rotation of the knob to reconnect the power when the door is open. While this apparatus is suitable for its intended purpose, the bracketing requires modification of an existing fuse block.
It would therefore be desirable to provide a less intrusive mechanism for preventing rotation of the operator in a direction that would reconnected power when the cabinet door is open.
One aspect of the present invention provides an operator assembly for controlling a disconnect having a rotary shaft adapted to receive a portion of a door-mounted knob and rotating in a first direction to connect electrical current through the disconnect, and rotating in a second direction to prevent electrical current from flowing through the disconnect. The operator assembly includes a housing configured to receive the rotary shaft, and a unidirectional coupling mechanism that is connected between the shaft and the housing, wherein the uni-directional coupling mechanism facilitates uni-directional rotation of the shaft in response to rotation of the operator assembly.
It is thus one object of the invention to prevent power from being connected and disconnected simply by rotating the operator housing.
In another aspect, the operator assembly includes a bi-directional coupling mechanism that couples the shaft and the handle with respect to both directions of handle rotation when the door is closed.
It is thus another object of the invention to enable current to be intuitively connected through the disconnect and to prevent current from flowing through the disconnect when the door is closed by rotating the handle in the corresponding direction.
In accordance with yet another aspect of the invention, the bi-directional coupling mechanism can be engaged by the user when the door is open by performing a predetermined sequence of events.
It is thus another object to enable a skilled user to intentionally connect power to the disconnect when the door is open while reducing the likelihood that power will be inadvertently connected.
In still another aspect, the operator assembly includes a clutch that engages the bi-directional coupling mechanism when either the door is closed or the user performs the predetermined sequence of events.
It is thus another object of the invention to provide a mechanism for activating the bi-directional coupling mechanism, and operating the uni-directional coupling mechanism when the bi-directional coupling mechanism is disengaged.
In another aspect, the clutch is operated by depressing a hub relative to the handle to engage the bi-directional coupling mechanism and releasing the hub relative to the handle to disengage the bi-directional coupling mechanism and engage the secondary coupling mechanism.
It is thus another object to engage the bi-directional coupling mechanism automatically when the door is closed, to selectively engage the bi-directional coupling mechanism when the door is open, and to automatically engage the uni-directional coupling mechanism when the bi-directional coupling mechanism is disengaged.
In another aspect, the operator assembly is carried by the shaft.
It is thus another object to provide an operator assembly that can be retrofitted to a pre-existing disconnect without requiring modification of the disconnect.
These and other aspects and advantages of the present invention will appear from the following description. In the description, reference is made to the accompanying drawings which form a part thereof, and in which there is shown by way of illustration, and not limitation, preferred embodiments of the invention. Such embodiments do not necessarily represent the full scope of the invention, and reference should therefore be made to the claims herein for interpreting the scope of the invention.
Referring to
Operator assembly 36 extends generally axially, and interfaces with door knob 26 and, in particular, with connector 28. Operator assembly 36 is thus operable by a user to connect power to fuses on fuse block 10, and disconnect power from fuse block 10. Operator assembly 36 preferably comprises a plastic, though one skilled in the art will recognize that any material suitable to withstand the stress and strain experienced during operation falls within the scope of the present invention.
Referring now to
Referring also to
A plurality of beveled ribs 60 extends axially along the radially inner surface of body 56. Ribs 60 are equally spaced circumferentially about body 56 to define a plurality of interposed recesses 62. A plurality of radially spaced teeth 59 extends axially out from the outer end of body 56, and are equally spaced circumferentially about body 56 to define a corresponding plurality of interposed recesses 61. A pair of opposing mounting flanges 57 extends radially out from the axially outer end of body 56, and includes a pair of apertures sized to receive corresponding screws 54.
Referring now to FIGS. 5 and 14–16, a uni-directional coupling mechanism 64 is provided in the form of a ratchet assembly that enables uni-directional operation to disconnect power from fuse block 10. Ratchet assembly 64 includes a bearing cup 66 having a hexagonal outer wall 68 that is sized to be received by ribs 60 such that rotation of inner shell causes cup 66 to correspondingly rotate. Cup 66 further includes an internal substantially cylindrical bore 70 forming a grooved ratchet chamber. Specifically, a track 73 defined by a plurality of axially extending arc-shaped grooves 71 (and corresponding teeth 75 interposed between adjacent grooves 71) defines the outer periphery of chamber 70.
Chamber 70 is closed at its axially inner end by a base 72 having a circular opening 74 extending centrally there through that is sized to loosely and rotatably pass shaft 22. A hexagonal cover 77 is provided and affixed to the axially outer end of bearing cup 66. Cover 77 is preferably transparent, and defines a central aperture 79 that matches aperture 74. As a result, rotation of shaft 22 does not directly cause bearing cup 66 and cover 77 to rotate.
Ratchet assembly 64 further includes a bearing carrier plate 76 having a generally cylindrical outer wall 78 having a diameter slightly less than the inner diameter of chamber 70. An aperture 85 extends axially through carrier plate 76, and defines a square or other suitable cross-section configured to snugly receive shaft 22 such that rotation of shaft 22 causes carrier plate 76 to rotate therewith. Specifically, outer wall 78 rides along grooves 71 as carrier plate 76 rotates within chamber 70 during operation.
A pair of opposing elongated rectangular cutouts forms pockets 78 in carrier plate 76 offset 180° with respect to each other. Each pocket 78 is defined by first guide wall 80 and a second support wall 82 oriented perpendicular to guide wall 80. Guide wall 80 is elongated with respect to support wall 82. Each pocket 78 receives a spherical bearing member 84 supported by one end of a compression spring 86 that is grounded at its other end by support wall 82. Each spring 86 biases its corresponding bearing member 84 against grooved track 73.
When a counterclockwise torque is applied to bearing cup 66, the force causes teeth 75 to bias bearing members 84 against the corresponding non-resilient guide walls 80. The counterclockwise torque is thus transferred to carrier plate 76. Accordingly, bearing cup 66, carrier plate, and shaft 22 all rotate counterclockwise.
On the contrary, when a clockwise torque is applied to bearing cup 66 as indicated by Arrow A, bearing cup 66 is caused to rotate clockwise. As bearing cup 66 rotates, the radial forces resulting from engagement between bearing members 84 and teeth 75 cause springs 86 to compress. The compression causes bearing members 84 to slide along guide wall 80 as they cam over teeth 75 and fall into adjacent grooves 71 whose surfaces are defined by a radius that generally match the radius of bearing members 84. Bearing members 84 continue to ratchet along track 73 as carrier plate 76 continues to rotate clockwise.
Referring now to
Referring to
Referring now to
Cylindrical body 50 is closed at one end by an axially front face 46 sized to be engaged by connector 28. Accordingly, when door 24 is closed, connector 28 depresses hub 44 against the force of spring 39.
An aperture 65 extends axially through hub 44, and defines a square cross-section configured to snugly receive shaft 22 such that rotation of hub 44 causes shaft 22 to also rotate. It should be easily appreciated, however, that shaft 22 and aperture 65 (along with the other shaft-engaging components) could assume any alternative cross-sectional shape without departing from the present invention. The axially outer end of aperture 65 defines a keyway 47 extending only partially into hub 44 sized to receive a pin 34 extending transverse from the axially outer end of shaft 22. Shaft 22 and hub 44 thus rotate in concert while keyway 47 prevents shaft 22 from being pulled through hub 44.
Referring also to
When bi-directional coupling mechanism 67 is engaged, pawls 52 and ribs 60 interlock hub 44 and shell 38 with respect to rotation. Accordingly, rotation of operator assembly 36, and in particular shell 38, in both the clockwise and counterclockwise directions causes hub 44 and shaft 22 to correspondingly rotate.
Referring again to
A plurality of radially spaced notches 51 are formed in the axially inner end of neck 48, and are equally spaced circumferentially about neck 48, to define a corresponding plurality of locking teeth 49 interposed between adjacent notches 51. Teeth 59 and recesses 61 of shell 38 are configured to interlock with teeth 49 and recesses 51, respectively, of handle 40. A pair of threaded apertures 45 extends axially into grip 42 and face corresponding mounting flanges 57. Screws 54 thus extend through flanges 57 and into apertures 45 to secure handle 40 to shell 38.
Referring also to
System Operation
Operation of operator assembly 36 will now be described with initial reference to
Rather, referring to
On the contrary, when a torque is applied to operator assembly 36 in the clockwise direction (i.e., in an attempt to connect power in fuse block 10), bearing member(s) 84 compress corresponding spring(s) 86 and ratchet along track 73. Accordingly, bearing cup 66 rotates about carrier plate 76 (and shaft 22), thus preventing power from being reconnected in fuse block 10. Furthermore, because operator assembly 36 is allowed to freely rotate in the clockwise direction, uni-directional coupling mechanism 64 provides tactile feedback that power is not permitted to be connected to fuse block 10 by simply rotating operator assembly 36. Moreover, if the user is attempting to disconnect power from fuse block 10, coupling mechanism 64 induces the user to rotate operator assembly 36 in the opposite, and correct, direction.
The present inventors have recognized that certain internal disconnect switches in fuse block 10 are configured to operate under a low amount of torque. The amount of torque necessary to cause bearing members 84 to ratchet along track 73 can be controlled at each individual pocket 78, for example, by adjusting the spring constant of spring 86, the geometric configuration of teeth 75, and the size of bearing members 84. Alternatively, the driving torque force can be controlled by the number of pockets 78 formed in carrier plate 76 as described above. Advantageously, the amount of torque necessary to cause bearing members 84 to ratchet along track 73 is less than the amount of torque necessary to operate the disconnect switch.
Referring now to FIGS. 7,9, and 12, bi-directional coupling mechanism 67 can be engaged in one of two ways. First, door 24 can be closed, thus causing connector 28 to depress hub 44 relative to inner shell 38 against the biasing forces of spring 39 as indicated by Arrow B. Secondly, bi-directional coupling mechanism 67 can be engaged by manually depressing hub 44 relative to operator assembly 36 by either depressing hub 44 directly, or by pulling handle 40 out, thus raising inner shell 38 relative to hub 44. Whether door 24 is closed or hub 44 is manually depressed relative to shell 38, pawls 52 become interdigitated with ribs 60 thus rotatably interlocking hub 44 and operator assembly 36. The beveled ends of pawls 52 and ribs 60 assist in engaging coupling mechanism 67. Because shaft 22 is coupled to hub 44, when operator assembly 36 is rotated clockwise and counterclockwise with bi-directional coupling mechanism 67 engaged, shaft 22 rotates along with operator assembly 36 causing power to be connected and disconnected, respectively.
It is thus appreciated that when door 24 is closed and a user wishes to access fuse block 10, the user actuates knob 26, which causes operator assembly 36 to rotate counterclockwise, thereby disconnecting power from fuse block 10. Once door 24 is open (disconnecting bi-directional coupling mechanism 67) and operator assembly 36 is rotated clockwise, uni-directional coupling mechanism 64 will prevent shaft 22 from reconnecting power in fuse block 10. Rather, the user must first perform a predetermined sequence of events by manually depressing hub 44 relative to shell 38 in order to reengage bi-directional coupling mechanism 67. While hub 44 is depressed, operator assembly 36 can be rotated clockwise to reconnect power in fuse block 10.
The invention has been described in connection with what are presently considered to be the most practical and preferred embodiments. However, the present invention has been presented by way of illustration and is not intended to be limited to the disclosed embodiments. For example, while the present invention is applicable to fuse blocks of the type described above, it should be appreciated that the present invention is applicable to any handle-operated device that would benefit from coupling mechanisms 64 and 67. Accordingly, those skilled in the art will realize that the invention is intended to encompass all modifications and alternative arrangements included within the spirit and scope of the invention, as set forth by the appended claims.
This application is a Continuation-In-Part of U.S. patent application Ser. No. 10/714,433 filed Nov. 14, 2003, now U.S. Pat. No. 6,881,909, which is in turn a Continuation-in-Part of U.S. patent application Ser. No. 10/298,326, filed Nov. 18, 2002, now U.S. Pat. No. 6,700,081, the disclosure of each of which is hereby incorporated by reference as if set forth in its entirety herein.
Number | Name | Date | Kind |
---|---|---|---|
1404865 | Kries | Jan 1922 | A |
1417920 | Jessen | May 1922 | A |
1812896 | Olley | Jul 1931 | A |
2053997 | Krcek | Sep 1936 | A |
2465079 | Fitzgerald | Mar 1949 | A |
3122615 | Chace | Feb 1964 | A |
3581032 | Christensen | May 1971 | A |
4405844 | Dizon et al. | Sep 1983 | A |
5493084 | Whitaker | Feb 1996 | A |
5609244 | Reiter | Mar 1997 | A |
6700081 | Houck, III | Mar 2004 | B1 |
6710697 | Houck, III | Mar 2004 | B1 |
6881909 | Houck, III | Apr 2005 | B1 |
Number | Date | Country |
---|---|---|
1193144 | May 1965 | DE |
1954 849 | Sep 1996 | DE |
0564173 | Jun 1993 | EP |
Number | Date | Country | |
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20050040019 A1 | Feb 2005 | US |
Number | Date | Country | |
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Parent | 10714433 | Nov 2003 | US |
Child | 10950887 | US | |
Parent | 10298326 | Nov 2002 | US |
Child | 10714433 | US |