US3873136A

US3873136A - Anti-twist service fitting for use with underfloor wiring duct

Info

Publication number: US3873136A
Application number: US376244A
Authority: US
Inventors: John R Curry
Original assignee: Square D Co
Current assignee: Schneider Electric USA Inc
Priority date: 1973-07-05
Filing date: 1973-07-05
Publication date: 1975-03-25
Anticipated expiration: 1992-03-25

Abstract

The fitting includes a collar, which extends upwardly from the duct to a point below the floor surface, a base having a slotted opening, and an adapter which is connected to the top of the collar. The base is placed on the floor surface over the collar and adapter, the top portion of the adapter being disposed within the opening of the base. After the base is angularly positioned, an annular clamping plate having tangs extending downwardly is then placed over the base and the tangs engage the slotted opening of the base. Screws extend through holes in the clamping plate and are threaded to the adapter and collar thus securing the base fixedly against the floor surface.

Description

United States Patent [191 Curry ANTI-TWIST SERVICE FITTING FOR USE WITH UNDERFLOOR WIRING DUCT [75] Inventor: John R. Curry, Oxford, Ohio [73] Assignee: Square D Company, Park Ridge, 111. [22] Filed: July 5, 1973 1 [21] Appl. No.: 376,244

[52] US. Cl 285/189, 285/330, 52/221 [51] Int. Cl. F161 5/00 [58] Field of Search 285/189, 12,330, 90; 52/221 [56] References Cited UNITED STATES PATENTS 3,047,650 7/1962 Reiland 52/221 X 3,334,457 8/1967 Hudson et al 285/189 X 3,408,094 10/1968 Flachbarth et a1 1. 285/330 X [in 3,873,136 [4 1 Mar. 25, 1975 Primary Examiner-Werner H. Schroeder Assistant Examiner-Peter Nerbun Attorney, Agent, or Firm-Harold). Rathbun 57 ABSTRACT The fitting includes a collar, which extends upwardly from the duct to a point below the floor surface, a base having a slotted opening, and an adapter which is connected to the top of the collar. The base is placed on the floor.surface over the collar and adapter, the top portion of the adapter being disposed within the opening of the base. After the base is angularly positioned, an annular clamping plate having tangs extending downwardly is then placed over the base and the tangs engage the slotted opening of the base. Screws 1 I extend through holes in the clamping plate and are threaded to the adapter and collar thus securing the base fixedly against the floor surface.

11 Claims, 5 Drawing Figures ANTI-TWIST SERVICE FITTING FOR USE WITH UNDERFLOOR WIRING DUCT BACKGROUND OF THE INVENTION Heretofore some of the floor wiring duct systems employed service fittings which resisted rotation by relying on the friction resulting from the contact of the outer periphery of a clamping plate with the periphery of the aperture of a service fitting base and the contact of the underside of said base with a floor surface.

Since it is desirable that service fittings do not rotate from present positions, reliance on friction is not adequate because an inadvertent force applied to the service fitting may overcome the frictional forces and result in the rotation of the service fitting.

SUMMARY OF THE INVENTION An anti-twist fitting in accordance with this invention is connectible to an underfloor wiring duct having an access opening and an upstanding collar extending upwardly a predetermined distance above the top surface of the main portion of the duct and terminating at a point below a floor surface thereby to accommodate a concrete floor of predetermined minimum thickness.

An anti-twist connecting means is provided thereby to connect the service fitting to the collar of the underfloor wiring duct. The connecting means includes an adapter member connectible to the top of the collar, a base of the service fitting having a slotted opening, the opening of the base being disposed around the top of the adapter, and a clamping plate fitted to the end of said adapter. The clamping plate has a plurality of tangs disposed along the outer periphery of the plate which engage the slotted opening of the base thereby holding fixedly the base of said service fitting in a preselected angular position.

It is an object of the invention to provide an improved service fitting which will resist rotation after being installed in a preselected angular position.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects and advantages of the invention will become apparent from the following description wherein reference is made to the drawings, in which:

FIG. 1 is a sectional view of a portion of an underfloor wiring duct provided with a service fitting in accordance with this invention;

FIG. 2 is a sectional view taken generally along the line 22 of FIG. 1;

FIG. 3 is a sectional view taken generally along the line 3-3 of FIG. 2;

FIG. 4 is an exploded perspective view of the service fitting of FIG. I, 2, and 3; and

FIG. Sis an exploded view similar to FIG. 4 but showing a modified service fitting.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a segment of an underfloor wiring duct embedded in a concrete floor ILA service fitting 12 in accordance with this invention is positioned over a circular access opening 13 in the duct 10.

Referring more particularly to FIG. 2, 3, and 4, the service fitting 12 includes a base 16 and a cover 18. An opposed pair of integral upstanding flanges 17 are provided on the base 16, and the cover 18 is secured to the flanges 17 by a plurality of screws 20 passing through respective openings in the cover and threaded into respective holes in the flanges 17.

The base 16 also has an opposed pair of integral upstanding flanges24 at right angles to the flanges 17, the flanges 24 extending within the cover 12 and being drilled and notched to serve as an anchoring means for various types of electrical receptacles (not shown). A bottom wall of the base 16 has a circular opening 26, the inner periphery of which is provided with a plurality of circumferentially spaced slots 28 for a purpose to be described.

One or more cables 29 oflimited flexibility within the duct 10 can pass through the opening 13 for connection to an electrical receptacle (not shown) within the cover 18. The cover 18 is shown as apertured for an electric power receptacle but a similar cover could be apertured for use with other receptacles such as a telephone service receptacle.

When not provided as a part of the duct 10, the fitting 12 also comprises a collar 30 internally threaded as at 32 and secured to the duct segment 10 at the access opening 13 by a pair of screws 34 received in diametrically opposed and radially directed slotted lugs 35. An adapter in the form ofa locking nipple 36 of the fitting 12 has an externally threaded lower portion 38, a pair of inner axially extending bosses 40 defining exterior diametrically opposed grooves 42 and a plurality of outwardly extending circumferentially spaced flange portions 44. Two of the flange portions 44 have respective openings 46 aligned respectively with the grooves An annular clamping plate 48 of the fitting 12 having a body portion 50 is provided with a pair of diametrically opposed elongated openings or slots 52 and a pair of diametrically opposed downwardly extending tangs 54.

In installation of the fitting 12, the collar 30 is inserted into an opening 11a in the floor l1 aligned with the opening 13 in the duct segment 10 and is secured to the duct segment by the screws 34. The length of the collar 30 is such that its upper edge is disposed below an upper surface of a floor covering 55 such as tile. The base 16 is then positioned on the floor covering 55 with its opening 26 over the opening 11a and set in a desired angular position. The locking nipple 36 is then inserted through the opening 26, and the threaded portion 38 is screwed into the collar 30 by use of a tool (not shown) which engages the flanges 44. The threaded portion 38 advances inwardly of the collar 30 until under surfaces 58 of the flanges 44 abut a top surface 60 of the base 16 about the opening 26 thus pressing an underside of the base 16 against the floor covering 55.

The plate 48 is then placed over the locking nipple 36 with the slots 52 positioned respectively over the openings 46 and the tangs 54 received respectively in two of the slots 28 in the periphery of the opening 26. Screws 61 are inserted through the slots 52 and the openings 46 and moved downwardly in the grooves 42 until the shanks of the screws 61 are received in the respective gaps formed by the grooves 42 and the threaded portion 32 of the collar 30. The screws 61 are turned and advance downwardly until their heads abut the plate 48 thereby preventing the disengagement of the tangs 54 from the slots 28. As the screws 61 are advanced downwardly, the threaded shank portions of the screws 61 bind between the threaded portions 38 of the nipple 36 and the collar 30 thus preventing relative rotation of the nipple 36 and the collar 30.

After the screws 61 are tightened, the cable 29 is pulled above the base 16 and connected to a receptacle (not shown), the cover 18 is then placed over the base 16 and the screws installed thereby securing the cover 18 to the base 16.

A service fitting 64 of another embodiment of the invention is shown in FIG. 5. It is for use with a lengthwise elongated access opening 66 of a duct 68 having an upstanding collar 72 defining the opening 66. The duct 68 is similar to the duct shown in Hudson et al. US. Pat. No. 3,334,457 issued Aug. 8, 1967. The top of the collar 72 is preferably positioned below the floor level sufficiently to accommodate a required minimum thickness of concrete. For a greater thickness, a collar extension as shown in the aforementioned patent may be used.

For securing the service fitting 64 to the duct, the fitting includes an adapter 74 having an annular upstanding collar 76 and an oblong base 77 having substantially annular upper-facing rim 78. The adapter 74 is provided with a pair of holes 79 for a purpose to be later described. In installation, the base 77 of the adapter 74 is disposed snugly in either the access opening 66 defined by the collar 72 or in the upper end portion of a collar extension (not shown). The adapter 74 is secured in position by a pair of screws 80, which are preferably of the self-tapping type, received respectively in an opposed pair of tapered recesses 81 in the portion 77 which, with the adjacent collar portion 72, define holes for the screws 80. Each of the screws 80 thread partly into the surface of the adapter 74 within the recesses 81 and partly into the adjacent inner surface of the collar portion 72 to provide a good electrical ground connection in and to hold the adapter 74 securely in place. The holes defined by the recesses 81 and the adjacent portions of the collar portion 72 are originally smaller than the diameter of the screws 80. Thus the natural resiliency of the adapter 74 and the collar portion 72 maintain the screws 80 under compression thereby holding the assembly securely together.

The fitting 64 also includes the base 16 of the principal embodiment. The upstanding collar 76 of the adapter 74 is received in the opening 26 of the base 16, and the base 16 is then rotated to the desired angular position with respect to the duct 68.

The base is secured to the adapter 74 by means of a clamping plate 84 having a generally annular body portion 86 with an integral annular lip 88 and a pair of tangs 90 extending upwardly, a pair of tangs 92 extending downwardly, and two pairs of

slots

94 and 96. The

lip 88 surrounds an opening 97 for receiving the collar 76 of the adapter 74. The clamping plate 84 is secured to the adapter 74 by a pair of screws 98 which are received in one of the pair of

slots

94 or 96 and threaded respectively into the holes 79 provided in the adapter. With the base 16 positioned in the desired angular position, the screws 98 are then inserted through one of the pair of

slots

94 or 96, depending on whether the plate 84 isinstalled with the lip 88 extending upwardly or downwardly, and then threaded into the holes 79. As the screws 98 are then tightened, either the

tangs

90 or 92 engage slots in the slotted inner periphery 28 of the opening 26 in the base 16 and the underside of the base 16 is placed in tight contact with the floor surface 55 (FIG. 1 and 2) thereby fixedly securing the base 16 at the selected angular position.

The clamping plate 84 is designed to allow the accommodation of variations in the distance between the surface of the concrete floor and the rim 78 of the adapter 74. When the distance is large, the plate 84 is installed with the lip 88 extending downwardly, as shown in FIG. 5. Thus, the lip 88 is disposed around the upper portion of the collar 76. When the rim 78 is at or slightly below the surface of the concrete floor, the plate 84 is installed with the lip 88 extending upwardly. The position of the plate 84 is inverted because the lower edge of the downwardly extending lip 88 will otherwise abut the rim 78 and thereby prevent the engagement of the tangs 92 with the slots 28. The installation of the clamping plate 86 with the lip 88 projected either upwardly or downwardly will determine whether tangs or 92 engage the slots 28 of the base 16, and whether the screws 98 are inserted in either

slots

94 or 96.

After the screws 98 are tightened and the cable 29 is pulled beyond the base 16 and connected, the cover 18 is placed over the base 16 and the screws 20 installed thereby securing the cover 18 to the base 16.

Thus it is apparent that there has been provided, in accordance with the invention, an anti-twist service fitting that fully satisfies the objects, aims, and advantages set forth above. While the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly it is intended to embrace all such alternatives, modifications, and variations as fall within the spirit and broad scope of the appended claims.

We claim:

1. A service fitting for an underfloor wiring duct, the fitting comprising a base having a circular opening for the passage of wires, a tubular adapter received in the circular opening in the base, and a clamping plate fixedly secured to the adapter and having a planular portion overlying the base for holding the base against a floor surface, characterized in that the opening in the base has a plurality of circumferentially, closely spaced slots about its periphery, the space between said slots being substantially equal and the clamping plate has an interlocking portion extending outwardly from I the plane of the planular portion overlying the base and received in a selected one of the slots, the base being fixedly held in a pre-selected angular position with respect to the clamping plate and adapter.

2. A service fitting as claimed in claim 1 wherein the base has upstanding flange portions and a cover of the fitting is secured to the flange portions.

3. A service fitting as claimed in claim 1 wherein the opening in the base is generally circular and the clamping plate has an additional projecting portion received in a slot diametrically opposite said selected slot.

4. A service fitting as claimed in claim 1 wherein a collar is provided to serve as a conduit for wires passing from an opening in a wiring duct through said adapter and opening in the base, and the adapter is fixedly secured to the collar.

5. A service fitting as claimed in claim 4 wherein the collar portion is circular and internally threaded, the adapter has a circular externally threaded lower portion threaded into the collar and a pair of axially extending diametrically opposed grooves in its outer surface, the intersection of the grooves with the threaded interior of the collar defining pair of gaps, a plurality of outwardly extending circumferentially spaced flanges on an upper portion of the adapter overlying the base, two of the flanges having respective openings aligned respectively with the gaps, and threaded screws passing through respective openings in the clamping plate and the openings in the flanges and threaded into the respective gaps, whereby the base, adapter and collar are held in non-rotatable relationship.

6. An underfloor wiring duct having an upstanding collar portion defining an access opening, and means for securing a base portion of a service fitting thereto, the base portion having a circular opening therethrough for the passage of wires, said securing means including a service fitting adapter secured to the collar and extending upwardly therefrom, a clamping plate fitted over the end of the adapter remote from the duct and having a planular portion overlying the base portion and clamping the base portion to a floor surface, means securing the clamping plate to the adapter, a plurality of circumferentially closely spaced slots about the periphery of the opening in the base portion said slots being substantially equal and the clamping plate having a tang angularly disposed with respect to the plane of the planular portion and received in a selected one of said slots to prevent relative rotation between the clamping plate and the base portion.

7. An underfloor wiring duct as claimed in claim 6 wherein the upstanding collar is formed integrally with 6 the duct.

8. An underfloor duct as claimed in claim 6 wherein the adapter has an upper collar portion and an oblong base defining an upwardly directed annular rim therebetween, a pair of diametrically opposed openings in the rim, and said base portion of the adapter being fixedly disposed within the access opening.

9. An underfloor duct as claimed in claim 8 wherein the clamping plate has a hole therethrough for receiving said upper collar portion of the adapter and a lip portion disposed around the periphery of said hole, said clamping plate being invertible to accommodate variations in the thickness of concrete in which said duct may be embedded, said lip portion extending through the opening in said base portion in a position of the clamping plate in which said lip portion extends downwardly toward said duct, and said tang is one of two tangs receivable respectively in selected ones of said slots.

10. An underfloor duct as claimed in claim 9 wherein one tang extends away from the body of clamping plate in the direction of the lip portion and the other tang extends in the opposite direction.

11. An underfloor duct as claimed in claim 10 wherein the clamping plate has two pairs of openings therethrough, two screws are received in a selected pair of the opening in the clamping plate depending on whether said lip is extending upwardly or downwardly, said screws being threaded into the holes in the rim of the adapter.

Claims

1. A service fitting for an underfloor wiring duct, the fitting comprising a base having a circular opening for the passage of wires, a tubular adapter received in the circular opening in the base, and a clamping plate fixedly secured to the adapter and having a planular portion overlying the base for holding the base against a floor surface, characterized in that the opening in the base has a plurality of circumferentially, closely spaced slots about its periphery, the space between said slots being substantially equal and the clamping plate has an interlocking portion extending outwardly from the plane of the planular portion overlying the base and received in a selected one of the slots, the base being fixedly held in a pre-selected angular position with respect to the clamping plate and adapter.

7. An underfloor wiring duct as claimed in claim 6 wherein the upstanding collar is formed integrally with the duct.