EXPANSION JOINT FOR CONNECTING RIGID CONDUIT WITH GROUNDING CONTINUITY

• US 3,783,178 A
• Filed: 08/03/1972
• Issued: 01/01/1974
• Est. Priority Date: 08/03/1972
• Status: Expired due to Term

• Current Assignee: Eversly V. Parkins, Robert A. Philibert, Robert Polimine
• Original Assignee: Eversly V. Parkins, Robert A. Philibert, Robert Polimine
• Inventors: Philibert, Robert A., Polimine, Robert, Parkins, Eversly V.
• Primary Examiner(s): Clay, Darrell L.
• Application Number:
  US05/277,828
• Time in Patent Office: 516 Days
• Field of Search: 174/35GC,78,84R,86,65G,12R 285/382.7,354,343,342,348,302 339/14R
• US Class Current: 174/86
• CPC Class Codes: F16L 25/01 specially adapted for realising electrical conduction between the two pipe ends of the joint or between parts thereof
• CPC Class Codes: F16L 27/1274 by means of a swivel nut
• CPC Class Codes: H01R 4/60 Connections between or with tubular conductors H01R4/56 takes precedence
• CPC Class Codes: H02G 3/06 Joints for connecting lengths of protective tubing or channels, to each other or to casings, e.g. to distribution boxes; Ensuring electrical continuity in the joint

Abstract

In order to protect personnel, promote safety and prevent equipment damage it is conventional for electrical conduits to be grounded with a high integrity ground. Because of the expansion and contraction which may take place in electrical conduits it is sometimes necessary to provide telescoping or expansion joints. The present invention relates to a rain-tight expansion joint which provides a high integrity ground without the use of an external bonding jumper. A grounding ring is included in a head assembly and a controlled pressure is applied so that the grounding ring makes firm electrical contact with the head portion of the expansion joint and with the conduit. Grounding rings fabricated from sheet metal and tubular stock are disclosed. An O-ring is used in the head assembly to contact the conduit and protect the interior of the expansion joint from the weather and atmospheric conditions. Means are provided for limiting the travel of the conduit so that the tapered and threaded end thereof cannot enter the sliding contact region and jeopardize the integrity of the ground.

Claims

1. An electrically conducting expansion joint comprising in combination:

a. a body member having first and second ends coupling a section of rigid conduit to another member with said first end thereof coupled to said another member by a means which provides for high integrity electrical continuity between said body member and said another member;

b. said body member having an internal size at its second end which is at least of sufficient size admitting a portion of said rigid conduit section therein;

c. head coupling means coupling a head member to said body member and which provides electrical continuity between said body member and said head member and wherein said head member includes an opening receiving an end of said rigid conduit section therethrough;

d. grounding ring confined between said head member and said rigid conduit section and encircling said rigid conduit section;

e. pressure producing means confined between said head member and said grounding ring for applying pressure between said grOunding ring and both of said head member and said rigid conduit section providing electrical continuity between said head member and said grounding ring and sliding electrical continuity between said grounding ring and said rigid conduit section; and

f. motion limiting means including a longitudinal extension of said grounding ring limiting the longitudinal motion of said rigid conduit section in the direction to remove it from said head member so that said electrical continuity between said head member and said rigid conduit section is not endangered.

2. The combination as set forth in claim 1 wherein said head member includes stop means limiting the pressure between said grounding ring and said head member and said rigid conduit section when said head member is coupled to said body member by said head coupling means.

3. The combination as set forth in claim 1 wherein said head member includes a recess retaining an O-ring in sealing contact with said head member and said rigid conduit section to provide a rain-tight seal between said rigid conduit section and said head member.

4. The combination as set forth in claim 1 wherein said motion limiting means further comprises:

a. a bushing coupled to the end of said rigid conduit member which is contained within said body member; and

b. and wherein said motion limiting means co-acts with said bushing and said head member.

5. The combination as set forth in claim 1 wherein said grounding ring is in the shape of a right circular cylinder with a longitudinal slot and an end of said right circular cylinder is bent over at a substantial angle to the axis of the cylinder and extends away therefrom.

6. The combination as set forth in claim 5 and including a plurality of slits through said bent over portion.

7. The combination as set forth in claim 5 wherein said pressure producing means comprises a compression grommet applying a pressure between said cylindrical portion of said grounding ring and said rigid conduit member and between said bent over portion of said grounding ring and said head member.

8. The combination as set forth in claim 7 and including stop means in said head member limiting the pressure applied by said compression grommet to said grounding ring.

9. The combination as set forth in claim 8 wherein said motion limiting means includes a bushing coupled to the end of said rigid conduit member which is contained within said body member.