US3312872A

US3312872A - Bus duct plug mounting device with improved interlocking means

Info

Publication number: US3312872A
Application number: US483639A
Authority: US
Inventors: Russell S Davis
Original assignee: ITE Circuit Breaker Co
Current assignee: Siemens Energy and Automation Inc; ITE Circuit Breaker Co
Priority date: 1965-08-30
Filing date: 1965-08-30
Publication date: 1967-04-04
Anticipated expiration: 1984-04-04

Description

' April 4, 1967 R s. DAVIS 3,312,872

BUS Duc PLu MOUNTING DEVICE WITH 7 IMPROVED INTERLOCKING MEANS Filed Aug. 30, 1965 2 Sheets-Sheet 1 NIH I N VEN TOR.

A ril 4, 1967 Filed Aug. :50, 1965.

R. S. DAVIS BUS DUCT PLUG MOUNTING DEVICE WITH IMPROVED INTERLOCKING MEANS 2 Sheets-Sheet 2 United States Patent BUS DUCT PLUG MOUNTING DEVICE WITH IMPROVED INTERLOCKING MEANS Russell S. Davis, Detroit, Mich, assignor to I-T-E (Zircuit Breaker Company, Philadelphia, Pa., 2 corporation of Pennsylvania Filed Aug. 30, 1965, Ser. No. 483,639 9 Claims. (Cl. 317-119) This invention relates to bus duct plugs in general and more particularly relates to novel means for mounting of the plug to a duct.

Bus duct is usually installed at a considerable height above floor level so that it is necesary for an electrician to use a' ladder in order to mount and dismount power tapping plugs to the duct. Plugs of relatively modest current ratings are of such great bulk and/ or great weight that an electrician must use both of his hands to safely handle such plugs. Under these circumstances it is very d fiicuIt for an electrician to support the plug with one hand while attempting to insert a fastening screw through a plug housing aperture into a threaded aperture in the duct casing.

The basic screw type securement means was character istic of early constructions. Because of the many difficulties encountered with this type of construction the prior art progressed by providing elongated slots with enlarged ends to cooperate with fastening screws with the heads of the fastening screws being insertable into the enlarged ends but being too large to pass through the slots. This solution is undesirable in that it requires that holes be formed in the duct casing and the entire plug weight I must be supported by the electrician while he lines up the plug screws with the enlarged ends. Another prior art attempt at solution of the problem was a fastening means which extended completely over the top of the duct housing. But this latter fastening means interfered with the mounting of a plug on the opposite side of the duct. Snap-onfastening means have been tried but they are not positive or safe and the snap-on clamping members are easily distorted so that this solution is totally unsuited for large size plugs. I

T'heinstant invention overcomes the disadvantages of prior art by providing hook means which engage external formations of the duct housing. These hook means are permanently mounted to the plug so as to be pivotable and slidable with respect to the plug. Pressure applying means acting between the hook means and plug housing drawthe-hook tips into firm holding engagement with the duct housing to positively secure the plug to the duct. These hook means are provided at both the upper and lower edges of the plug housing. A blocking means secured to the plug housing limits or essentially prevents pivotable movement of theupper hook means so that this hook means may act as a fixed pivot for the plugrelative to the duct housing during the initial mounting of the plug. g Accordingly, a primary object of the instant invention is to provide a novel means for the securement of busduct plugs to a bus duct with this means providing a positive securement requiring relatively little time to make.

Another object is to provide a fastening means of this type which will not interfere with the mounting of a plug on the opposite side of the duct.

Still another object is to provide a fastening means of this type which is permanently mounted to the plug and does not require the handling of separate members.

A further object is to provide a fastening means of this type which does not require that special apertures or indentations formation be formed in the duct housing.

These as Well as other objects of this invention will be- 3,3l2,872 Patented Apr. 4, 1967 come readily apparent after reading the following description of the accompanying drawings in which:

FIGURE 1 is a perspective of a bus duct plug including the novel fastening means of the instant invention.

FIGURE 2 is a fragmentary rear elevation showing the plug of FIGURE I mounted to a bus duct.

FIGURES 3A and 3B are an end and bottom view, respectively, of the structure shown in FIGURE 2 looking in the direction of

arrows

3A, 3A and 3B, 3B respectively, of FIGURE 2.

FIGURE 4 is a side elevation showing various positions that the mounting hook may assume.

FIGURE 5 is a side elevation of one of the mounting hooks.

FIGURES 6 and 7 are elevations of the mounting hook looking in the direction of arrows 6-6 and 7-7, respectively, of FIGURE 5.

Now referring to the figures. Bus duct plug 10 is provided with rectangular house 19 having front face 11 with an aperture 12 therein. Bus bar engaging plug in

fingers

13, 14, 15, 16, maintained in spaced insulating relationship by insulator block 17 within housing 19, extend through aperture 12 forwardly of front wall 11 to engage the bus bars (not shown) of bus duct 50 (FIGURE 2) when plug 10 is mounted thereto. Plug 10 also includes circuit interrupting means, in this case fuses (not shown), mounted within housing 19.

In order to mount plug 10 to bus duct casing 51, plug 10 is provided with upper 21, 25 and lower 22, 26 hook members mounted to plug housing end walls 23 and 24 (FIGURESA) in a manner to be hereinafter explained. Since each of the

hook members

21, 22, 25 and 26 is of identical construction and is mounted in the same manner, for the sake of brevity and without loss of clarity, only hook member 25 and its mounting will be described in detail with particular reference to FIGURES 5 through 7 Member 25 is generally L-shaped having elongated leg 31 extending at right angles to elongated leg 32. The end of leg 31 remote from leg 32 is turned inwardly toward leg 32 to provide hook tip 33 with open mouth 34 facing leg 32. Spaced

parallel ears

35, 36 extend from opposite edges of leg 32 away from hook tip 33 and lie in planes generally perpendicular to the longitudinal axis of legs 31;

Bars

35, 36 are provided with aligned

elongated apertures

35a, 36a, respectively, extending generaly parallel to the longitudinal axis of web 31.

Slots

35a, 36a are formed at a point near the center of leg 32. Threaded aperture 37 is formed in leg 32 at a position near the-end of leg 32 remote from leg 31.

' One leg 42 of angle 40 is afiixed to end wall 24 in abutment therewith while the other leg 41 of angle 40 is positioned in the same plane as front wall 11. Pin 44, having an enlarged slotted head at one end and threads at the other end, extends through aligned apertures 35a,

36a and is received by aligned threaded apertures (not shown) in leg 42 and end wall 24. Pin-slot means 44,- 35a, 36a guides member 25 forpivotal and linear motion with respect to plug housing 19.

Clampingscre'w 46 is mounted in aperture 37 with the head of screw 46 being positioned between

ears

35, 36 and the free end of screw 46 being engageable with leg 41, for a reason to be hereinafter explained. Screw 48 is received by aligned threaded apertures (not shown) in leg 42 and side wall 24 with the head of screw 48 being positioned in the plane of ear 36 adjacent to the edge 36b of ear 36 which extends generally parallel to the longitudinal axis of leg 31. Screw 48 is so positioned relative to pin 44 and edge 36b that member 25 is restricted to motion essentially parallel to the axis of aligned slots -35a, 36a for a reason which will hereinafter be explained. It is noted that screws similar to 48 are not provided for

hook members

21, 22 and 26 so that these members may pivot about pin 44 to the dotted line position A of FIGURE 4.

In order to mount plug to casing 51 of bus duct 50 (FIGURES 2, 3A and 3B) hook member is moved to the dotted line position B of FIGURE 4 and screws 46 of

hook members

22 and 26 are backed out so that these members, being acted upon by gravity, will assume positions corresponding to the dotted line position A of FIGURE 4. The hook tip of member 25 is placed over the upward protrusion 55 along the upper edge of duct casing 51. Plug 10 is then moved longitudinally along bus duct 50 until interlock finger 54 (FIGURE 1) is aligned with a cooperating aperture (not shown) in duct casing 51. An access aperture cover (not shown) of duct 50 is then moved to open position permitting interlock finger 54 to move into duct casing 51 as plug 10 pivots about the hook tip of member 25 to a position where front wall 11 is parallel to the confronting wall of duct casing, 51. In this position, plug-in

fingers

13, 14, 15, 16 electrically engage individual bus bars (not shown) of bus duct 50 and the hook tip of member 21 engages protrusion 55. The function and operation of interlock finger 54 is shown and described in detail in the I. B. Cataldo et al. US. Patent 3,048,672 issued Aug. 7, 1962, for a Safety Bus Duct Plug.

At this point plug 10 requires no further support from the installing electrician. Screw 46 mounted to hook member 25 is now tightened to draw member 25 to a position corresponding to the dotted line position C of FIGURE 4. Hook member 21 is moved to, and maintained in, holding position by tightening its screw 46. One and then the other of

hook members

22 and 26 is pivoted upwardly with the hook tip thereof moving forward of downward protrusion 56 along the lower edge of duct casing 51 and is then moved to clamping position by rotating screw 46 of the

particular hook member

22 or 26 until this member reaches its holding position (corresponding to position C of FIGURE 4). Now the position of the particular screw 46 prevents either linear or pivotal movement of

members

22 and 26.

Thus, it is seen that the instant invention provides a novel means for positively securing a bus duct plug to a bus duct casing. The means are so constructed that all of the necessary elements are permanently afiixed to the plug and no special apertures or indentations are required in the bus duct casing.

Although there has been described a preferred em bodiment of this novel invention, many variations and modifications will 'now be apparent to those skilled in the art. Therefore, this invention is to be limited, not by the specific disclosure herein, but only the appending claims.

The embodiments of the invention in which an exclusive privilege or property is claimed are defined as follows:

1. A bust duct plug comprising a plurality of bus bar engaging fingers; a housing to which said fingers are secured; said housing having a front wall with an aperture through which said fingers extend forwardly of said front wall; said housing also having first and second end walls extending rearwardly from opposite first and second edges, respectively, of said front wall; mounting means for securing said plug to a bus duct casing; said mounting means including upper and lower portions having individual open hook portions facing one another and projecting forward of said front wall; said lower portion including a member having one of said hook portions at one end thereof, pin-slot means mounting the other end of said member to said first end wall; said pin-slot means defining a pivot for said member extending generally parallel to said front wall; said pin-slot means also defining means guiding said member for linear movement of said one hook portion toward and away from said front wall; an adjustable force applying means acting between said housing and second member for operating the latter to a holding position and holding the member at said position.

2. A plug as set forth in claim 1 in which said pinslot means includes an elongated slot in said member and a pin mounted to said wall and extending into said slot.

3. A plug as set forth in claim 2 in which the force applying means is mounted to said member.

4. A plug as set forth in claim 3 in which the force applying means comprising ascrew positioned to the rear of said slot.

5. A plug as set forth in claim 1 in which said member includes a first section and a second section at one end of said first section; said hook portion of said member positioned at the end of said first section remote from said second section; said hook portion having an open side facing said second section.

6. A plug as set forth in claim 5 in which said member includes spaced ears extending from said second section away from said first section; said pin-slot means including aligned elongated slots in said ears.

'7. A plug as set forth in claim 5 in which said pinslot means includes an elongated slot in said member and a pin mounted to said wall and extending into said slot;

said slot extending generally parallel to said first section.

8. A plug as set forth in claim 1 in which said upper portion includes an additional memberihaving another of said hook portions at one end thereof, additional pinslot means mounting the other end of said additional member to'said first wall; said additional pin-slot means defining a pivot for said additional member extending generally parallel to said front wall; said additional pinslot means also defining means guiding said additional member for linear movement toward and away of said another hook portion toward and away from said front wall; an additional force applying means acting between said housing and said additional member for operating the latter to a holding position and holding the additional member at this position.

9. A plug as set forth in claim 8 also comprising an element extending from said side wall into the path of said additional member to restrict pivotal movement thereof.

References Cited by the Examiner UNITED STATES PATENTS 3/1963 Sparkes 339-91 ROBERT K. SCHAEFER, Primary Examiner. I

a I. R. SCOTT, Assistant Examiner.