US 2972002 A
Description (OCR text may contain errors)
Feb. 14, 1961 I T. A. WAYMAN 2,972,002
FLUID-TIGHT JOINT AND CABLE MOUNTING Filed Jan. 28, 1958 Milli IIIIIIIIIHIIIIIHIIIM Illll INVENTOR TED A. WAVMA/V 3/? BY M-a ATTORNEY IIIIIHIJIIIIIIIIIMMIIIIIIIH United States Patent 2,972,002 FLUID-TIGHT JOINT AND CABLE MOUNTING Ted A. Wayman, Youngstown, Ohio. The M. & W. Electric Manufacturing Company, Inc., P.0. Box 87, East Palestine, Ohio) Filed Jan. 28, 1958, Ser. No. 711,687 2 Claims. (Cl. 174-65) The present invention relates to casings for electrical measuring instruments and more particularly to such casings having connectors for making fluid-tight joints between the casings and electric cables which enter and terminate within the casings.
In general, the present invention provides casings such as those used to house watt-hour meters on the outside of buildings, having cable connectors of the knock-out type in which a male socket is insertable into and removable from an opening through a wall of the casing from within the casing. A nut outside the casing secures the socket in place and the socket has a projection within the casing which contacts another wall of the casing to hold the socket against rotation when the nut is turned. The socket and nut compress between them an elastic deformable bushing into sealing relationship with an electric cable passing through the bushing.
The more specific features and objects of the invention will appear more fully below from the following detailed description considered in conjunction with the accompanying drawing, which discloses a preferred embodiment of the invention. It is to be expressly understood, however, that the drawing is not designed for the purpose of defining the limits of the invention, but is designed for purposes of illustration only, reference for the former purpose being had to the appended claims.
In the drawing, in which similar reference numerals denote similar elements throughout the several views:
Figure l is an assembly view partly in cross-section of a casing according to the present invention;
Figure 2 is a right side view of the structure of Figure 1;
Figure 3 is an exploded perspective view of various parts of a casing according to the present invention; and
Figure 4 is a view similar to Figure l but with the parts exploded.
Referring now to the drawing in greater detail, there is shown a casing for an electrical measuring instrument, indicated generally at 1. Casing 1 houses, for example, a conventional watt-hour meter (not shown) secured on the outside of a building. Casing 1 comprises a unitary pair of angularly related walls 3 and 5 of sheet metal. Wall 3 has a circular opening 7 thereth-rough for the reception of an electric cable 9 which terminates within casing 1 in electrical connection with the meter therein.
Casing 1 includes means for sealingly securing cable 9 in opening 7, comprising an electric cable connector indicated generally at 11 and including a hub or annular socket 13 movable relative to the walls of easing 1. Socket 13 is of the knock-out type in that it is insertable into and removable from opening 7 from within the casing. Socket 13 includes an enlarged head 15 of a diameter greater than opening 7 and a reduced, generally cylindrical externally screw-threaded male portion 17 which projects outwardly through opening 7 and is of a diameter less than opening 7 so that it may move radially relative to the marginal edges of opening 7. The interior surface of portion 17 comprises a forward cylindrical portion 19 extending from the forward end of socket 13 most of the length thereof and terminating at its rear or inner end in a truncated conical portion 21 which defines a radially inwardly extending annular shoulder on the inner end of socket 13.
A lock nut 23 has an internal, screw-threaded cylindrical surface 25 extending from the rear and most of the way toward the front end of nut 23 and terminating in a radially inwardly extending annular shoulder 27 bounded inwardly by a truncated conical surface 29.
An elastic deformable sealing ring 31 of a material such as neoprene or other rubber or the like is disposed in sealing relationship between head 15 of socket 13 and the inner side of wall 3 about opening 7. Ring 31 is of an inside diameter greater than the greatest outside diameter of externally screw-threaded male portion 17 of socket 13 and in the illustrated embodiment ring 31 is of an inside diameter the same as opening 7.
Thus, when lock nut 23 is screwed down upon male portion 17 of socket 13, the inner end of nut 23 will eventually abut and turn against the outer side of wall 3 about opening 7. For this purpose, the least outside diameter of nut 23 is substantially greater than the diameter of opening 7. Upon such contact, socket 13 will be drawn outward through opening 7 and sealing ring 31 will be compressed into sealing relationship. A very important feature of the present invention comprises the provision of means for preventing turning movement of socket 13 relative to the walls of casing 1, and in the illustrated embodiment this means takes the form of a projection 33 extending radially outward from and integral with enlarged head 15 and of a radial extent substantially greater than any other portion of head 15. As seen by comparison of Figures 1 and 2 (Figure 2 being in effect a view axially of connector 11 from within the casing) projection 33 contacts wall 5 and resists the tendency of socket 13 to turn counterclockwise as seen in An elastic deformable bushing 35 of a material such as neoprene or other rubber or the like forms the actual seal between cable 9 and the remainder of connector 11. Bushing 35 has an axially extending perforation 37 therethrough of a cross-sectional configuration corresponding to the outer cross-sectional contour of cable 9, which is oval in the illustrated embodiment. Bushing 35 has a pair of external truncated conical surfaces 39 and 41 at either end thereof and an external cylindrical surface therebetween extending most of the length of bushing 35 and terminating at its ends in surfaces 39 and 41. Cylindrical surface 43 is in contact with all of cylindrical portion 19 of the interior surface of socket 13 and extends a distance forward of the forward end of socket 13. Truncated conical portion 21 of the interior surface of socket 13 is in contact with all of conical end surface 39 of bushing 5 and the inner end of bushing 35 terminates a distance short of the rear end of conical surface portion 21.
A sleeve 45 has a configuration complementary to that of the internal surfaces of annular shoulder 27 on nut 23 and conical end surface 41 of bushing 35 and is disposed within nut 23 in contact with those surfaces. Sleeve 45 is formed of a relatively rigid but workable material which is less readily deformable than the material of bushing 35 and is preferably a metal such as aluminum, aluminum alloy, bronze or mild steel. Sleeve 45 has a generally radially disposed flange portion 47 from which extends forwardly and radially inwardly a truncated conical portion 49. Substantially the entire inner surfaces of shoulder 27 of nut 23 are in contact with corresponding complementary surfaces of sleeve 45, but the inner conical surface of sleeve 45 extends a distance forward of the forward end of bushing 35. The least internal diameter of sleeve 45 is greater than any diameter of perforation 37 of bushing 35.
The friction between bushing 35 and sleeve 45 is greater than the friction between nut 23 and sleeve 45 so that relative movement between any of these three elements will occur preferentially between the latter pair.
Radially inwardly extending annular shoulder 27 and the corresponding shoulder defined by conical surface 21 on socket 13 are spaced apart a distance such that when the inner end of lock nut 23 is tightened down on the outer side of wall 3 about opening 7 and sealing ring 31 is compressed between enlarged head 15 and the inner side of wall 3 about opening 7, these shoulders will coact to compress between them bushing 35 into tight sealing contact with cable 9. Sleeve 45 is so proportioned as to preserve this relationship.
Although the present invention has been described in connection with preferred embodiments, it is to be understood that modifications and variationsmay be resorted to without departing from the spirit or scope of the invention, as those skilled in this art will readily understand. Such modifications and variations are considered to be within the purview and scope of the invention as defined by the appended claims.
What is claimed is:
1. A casing for an electrical measuring instrument, comprising a wall, the wall having an opening therethrough, an electric cable extending through the opening, and means for sealingly securing the cable in the opening, said means comprising an annular socket having an enlarged head at its inner end disposed withinthe casing, the head being of a diameter larger than the diameter of the opening, an elastic deformable sealing ring sealingly disposed between the enlarged head of the socket and the inner side of the wall of the casing about the opening, the socket being movable relative to the casing and having a reduced generally cylindrical externally screw-threaded portion projecting outward through the opening, a lock nut screw-threadedly carried by the reduced portion disposed outside the casing having an inner end of a diameter larger than the diameter of the opening, an elastic deformable bushing disposed within the socket and the lock nut about the cable, the inner end of the socket and the outer end of the lock nut having radially inwardly extending annular shoulders spaced apart a distance such that when the inner end of the lock nut is tightened down on the outer side of the wall of the casing about the opening and the sealing ring is compressed between the head of the socket and the innerside of the wall of the casing about the opening, the shoulders will coact to compress between them the bushing into tight sealing contact with the cable.
2. A casing for an electrical measuring instrument as claimed in claim 1, and a sleeve of a material less readily deformable than the bushing, the sleeve being disposed between the bushing and the shoulder of the lock nut, the friction between the sleeve and the bushing being greater than the friction between the sleeve and the lock nut.
References Cited in the file of this patent UNITED STATES PATENTS 1,880,081 Frederickson Sept. 27, 1932 2,369,413 Rusz Feb. 13, 1945 2,454,767 Biushaber Nov. 30, 1948 2,651,529 Wayman Sept. 8, 1953 2,672,500 Bondon Mar. 16, 1954 2,816,949 Curtiss Dec. 17, 1957 2,827,509 Wayman Mar. 18, 1958 UNITED STATES PATENT OFVFICE CERTIFICATE OF CORRECTION Patent; No, 2,972,002 February 14 1961 Ted A0 Wayman It is hereby certified that error appears in the above numbered patent requiring correction and that the sa id Letters Patentv should read as corrected below.
Column 2, line 36, after "in" insert, Figure 2 upon corresponding turning movement of nut 23 Signed and sealed this 24th day of October 1961c,
*IRNEST W. SWIDER Commissioner of Patents USCOMM-DO UNITED STATES ATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 2,972,002 February 14 1961 Ted Aa Wayman It is hereby certified that error appe' ars in the above numbered patent requiring correction and that the said Letters Patent should read as 'correctedbelow.
Column 2, line 36, after "in" insert Figure 2 upon corresponding turning movement of nut 230 Signed and sealed this 24th day of October 1961;,
ERNEST W. SWIDER DAVID L. LADD Lttesting Officer Commissioner of Patents USCOMM-DC-