Motor control center units with multi-purpose shutter cams and related units

Patent metadata

Field	Value
Publication number	US-2018152007-A1
Application number	US-201715786248-A
Country	US
Kind code	A1
Filing date	Oct 17, 2017
Priority date	Nov 29, 2016
Publication date	May 31, 2018
Grant date	—

Abstract

Motor control centers have units or buckets with multi-purpose shutter cams that slide shutters right and left to controllably block access to a portal of an isolation lead screw that can extend and retract power connectors and that provides one or more safety interlock engagement features that prevent certain actions depending on the operating state of the buckets.

First claim

That which is claimed is:

1 . A bucket, comprising:
a bucket housing with laterally spaced apart sidewalls and at least one front panel; an operator handle residing in front of the front panel and having an inwardly extending drive shaft; a shutter cam attached to the drive shaft, wherein the shutter cam comprises a first cam segment with a curvilinear outer perimeter and a second cam segment with a curvilinear outer perimeter; and at least one shutter in communication with the shutter cam, the at least one shutter comprising a primary body with a shutter portal, the at least one shutter further comprising first and second laterally spaced apart outwardly projecting members that reside at a level below the shutter portal, wherein the first cam segment of the shutter cam engages the first member to laterally slide the shutter in a first direction to a position that misaligns the shutter portal with a socket of a lead screw in the bucket when the operator handle is in a first position, wherein the first cam segment of the shutter cam engages the second member to laterally slide the shutter in a second direction opposite the first direction to a position that aligns the shutter portal with the socket of the leadscrew when the operator handle is in a second position, and wherein the second cam segment provides at least one interlock engagement feature for releasably engaging at least one of a cabinet lock pin, a manual key lock and a door latch that prevents the operator handle from rotating.

2 . The bucket of claim 1 , wherein the second cam segment resides behind the first cam segment, in a longitudinal direction associated with a front to back direction of the bucket housing, and wherein the at least one shutter comprises a lateral extension with a downwardly extending planar vertically oriented segment residing above the drive shaft and positioned longitudinally between the first and second cam segments of the shutter cam, the downwardly extending planar vertically oriented segment comprising the first and second laterally spaced apart outwardly projecting members.

3 . The bucket of claim 1 , wherein the first and second cam segments are joined at a neck portion that has a channel that receives the drive shaft, and wherein the first cam segment has a curvilinear outer perimeter portion facing an adjacent longitudinally and laterally spaced apart curvilinear perimeter portion of the second cam segment.

4 . The bucket of claim 1 , wherein the shutter cam is a three dimensional single monolithic member, and wherein the shutter cam further comprises a first forwardly projecting segment attached to the first cam segment and a second forwardly projecting segment attached to the second cam segment.

5 . The bucket of claim 1 , wherein the first cam segment has a diameter that is less than a maximal radius of the second cam segment, the radius measured from a centerline of the drive shaft.

6 . The bucket of claim 1 , wherein the second cam segment has a portion of the outer perimeter that is adjacent a portion of the outer perimeter of the first cam segment with a curvilinear gap space between the adjacent portions.

7 . The bucket of claim 1 , wherein the shutter cam further comprises at least one of:
(i) a first forwardly projecting segment attached to the first cam segment and a second forwardly projecting segment attached to the second cam segment; (ii) at least one lug access aperture to thereby allow access to a phase A, B or C lug screw in an OFF position associated with non-conduction; or (iii) a planar rear surface with the second cam segment having an outer perimeter wall that is orthogonal to the planar rear surface and projects rearward a distance from the planar rear surface of the second cam segment, and optionally wherein the second cam segment has a portion of the outer perimeter that faces a curvilinear gap space that has a circumferential angular extent, measured from a center of the shaft, that is between 90-270 degrees.

8 . The bucket of claim 1 , further comprising a laterally extending cabinet lock pin residing behind the shutter cam in the bucket housing, the laterally extending cabinet lock pin attached to an actuator rod that slidably moves the cabinet lock pin between engaged and disengaged positions, wherein the actuator rod extends forward toward the operator handle a length sufficient to engage a first portion of the second cam segment of the shutter cam as the at least one interlock feature of the second cam segment and block the operator handle from rotating to an ON position as the first position when the cabinet lock is in the engaged position.

9 . The bucket of claim 8 , wherein a different second portion of the outer perimeter of the second cam segment of the shutter cam resides adjacent the actuator rod when the actuator rod is in the engaged position as a second of the at least one interlock feature and blocks movement of the actuator rod when the operator handle is in the ON position as the first position to thereby prevent the cabinet lock pin from being moved to the disengaged position.

10 . The bucket of claim 8 , wherein the outer perimeter of the second cam segment comprises a straight portion adjacent a curvilinear outer portion, and wherein the actuator rod extends over the straight portion as the first portion to engage the second cam segment of the shutter cam and block the handle from rotating to the ON position when the cabinet lock is in the engaged position.

11 . The bucket of claim 1 , wherein the second cam segment of the shutter cam has a lower interior recessed space as the door interlock feature as the at least one interlock feature and that releasably engages a spring-loaded arm to thereby block the shutter cam from rotating from OFF to ON when a door of the bucket is open.

12 . The bucket of claim 1 , further comprising a door latch that is attached to the shutter cam and controllably engages a cabinet door to prevent a cabinet door from opening if the operator handle is any position other than RESET.

13 . The bucket of claim 1 , further comprising a door latch that is attached to the first cam segment of the shutter cam and extends laterally outward from the shutter cam and that prevents the door latch from retracting if the operator handle is in any position other than RESET.

14 . The bucket of claim 13 , wherein the door latch comprises laterally spaced apart slots that engage first and second laterally spaced apart latch engagement features of the first cam segment of the shutter cam.

15 . The bucket of claim 1 , wherein the curvilinear outer perimeter of the second cam segment comprises a straight portion between two adjacent arcuate portions.

16 . A motor control center (MCC), comprising:
a cabinet housing with first and second sidewalls defining an enclosure with a plurality of compartments, the compartments configured to removably receive a plurality of units, wherein at least one of the units comprises:
a unit housing having a front and opposing laterally spaced apart sidewalls that extend rearward of the front of the unit housing;
an operator handle residing in front of the front panel and having an inwardly extending drive shaft;
a shutter cam attached to the drive shaft, wherein the shutter cam comprises a first cam segment and a second cam segment, and wherein the second cam segment is parallel with the first cam segment and is offset in a front to back direction of the unit housing to reside behind the first cam segment;
a shutter in communication with the shutter cam, the at least one shutter comprising

Assignees

• Eaton Corp

Inventors

• Kroushl Daniel Boyd
• Beard Alfred Gregory
• Yee Edgar

Classifications

• H01H71/56

  actuated by rotatable knob or wheel · CPC title

• H02B1/38

  Hinged covers or doors · CPC title

• H02B11/133

  with interlock · CPC title

• H02B1/36 Primary

  with withdrawable units · CPC title

• H01H9/22

  for interlocking between casing, cover, or protective shutter and mechanism for operating contacts {(explosion-proof cases H01H9/045; built-in fuses and interlocking mechanisms H01H9/104; by automatic release of circuit breakers H01H71/126)} · CPC title