US 3861778 A
An electrical connector comprises a rubber or flexible housing with a bore in which a tubular insert with a flange is embedded. The other end of the tubular insert can be tapered with external threads on which a nut may be tightened. The flange of the insert has a plurality of openings into which the rubber material of the housing flows when it is embedded in said housing by molding. The end of the insert may have axial slots therein so as to grip the outer surface of a cable passing therethrough upon tightening of the nut.
Claims available in
Description (OCR text may contain errors)
United States Patent 1' [191 Capra ELECTRICAL CONNECTOR WITH STRAIN RELIEF  Inventor: Peter Capra, Newark, NJ.
 Assignee: Sola Basic Industries Inc.,
 Filed: May 22, 1974  Appl. No.: 472,183
 U.S. Cl 339/103 R, 174/65, 285/161, 339/107  Int. Cl II0lr 13/58  Field of Search 339/103 R, 103 C, 103 M, 339/107; 174/65, 153; 285/161, 341, 348
 References Cited UNITED STATES PATENTS 3,430,187 2/1969 De Man et al. 339/103 R Jan. 21, 1975 3,796,504 3/1974 Marechal 339/103 R X Primary Examiner-R0y Lake Assistant Examiner-DeWalden W. Jones Attorney, Agent, or FirmSmythe & Moore  ABSTRACT An electrical connector comprises a rubber or flexible housing with a bore in which a tubular insert with a flange is embedded. The other end of the tubular insert can be tapered with external threads on which a nut may betightened. The flange of the insert has a plurality of openings into which the rubber material of the housing flows when it is embedded in said housing by molding. The end of the insert may have axial slots therein so as to grip the outer surface of a cable passing therethrough upon tightening of the nut.
7 Claims, 7 Drawing Figures ELECTRICAL CONNECTOR WITH STRAIN RELIEF i The present invention relates to an electrical connector for connecting an electrical cable to a socket or a plug, and more particularly, to a connector wherein the cable is gripped upon tightening of a nut.
Many forms of electrical connectors have been provided in which the terminal ends of an electrical conductor cable is secured within the connector housing and connected electrically to a socket or plug retained within the housing. One form of such a connector comprises a housing in one end of which is secured an insert and a nut is tightened on the otherend of the insert. The insert is generally provided with some sort of strain relief structure to grip securely the cables. The insert is generally provided with an external flange which is secured within an inner annular slot within the housing. However, tightening of the nut upon the insert caused the insert to grip securely the cable, but in many instances, the insert was loosely received within the housing. As a result, the connector was unsatisfactory since the insert was movable within the housing. Efforts to form the insert and housing to closer tolerances so that the insert was firmly received within the housing resulted in a rapid increase in the cost of manufacturing the connector. Also, making the housing and insert as a single integral unit generally resulted in a complicated and expensive connector which again was unsatisfactory. Examples of prior connectors are found in US. Pat. Nos. 3,667,783, and 3,123,662.
One of the objects of this invention is to provide an improved electrical connector within which an electrical cable is connected to a socket or plug.
According to one aspect of the present invention, an electrical connector may comprise a housing of plastic material having a bore therethrough within one end of which is positioned a socket or a plug. In the other end, a tubular insert has an external flange at one end thereof embedded in said housing, the flange having a plurality of openings through which the plastic of the housing has entered. The other end of the insert can be tapered inwardly with external threads thereon and is adapted to receive an electrical cable therethrough. A nut is threaded upon the tapered end of the insert and has an end portion which is engageable with the insert flange upon being tightened. The tapered end of the insert may be provided with a plurality of axial slots so as to grip tightly the outer face of the cable upon tightening of the nut. The insert also may have straight walls with threads thereon.
Other objects, advantages and features of the present invention will become apparent from the accompanying description and drawings, which are merely exemplary.
In the drawings:
FIG. 1 is a side elevational view of an electrical connector incorporating the present invention;
FIG. 2 is an elevational view from the plug end of the conductor of FIG. 1;
FIG. 3 is a view similar to that of FIG. 1 but in enlarged scale and with a portion of theconnector being shown in section;
FIG. 4 is a sectional view taken along the line 4-4 of FIG. 3;
FIG. 5 is an end elevational view of the insert component shown in FIG. 3;
FIG. 6 is a side elevational view of the insert of FIG. 5 with a portion thereof being shown in section; and
FIG. 7 is a side elevational view of a modified form.
Proceeding next to the drawings wherein like reference symbols indicate the same parts in the various views, a specific embodiment of the present invention will be described in detail.
The electrical connector of the present invention is indicated generally at 10 in FIGS. 1-3 and comprises a rubber or similar material housing 11 having a plurality of longitudinally extending ribs 12 on the outer surface thereof. The housing 11 is tubular and comprises a bore 13 (FIG. 3), in the outer end of which is secured a conventional plug 14 comprising a pair of electric terminals or prongs 15 and ground terminal 16. In place of plug 14, an electrical socket may also be used. The plug 14 is retained in position within the housing by a suitable structure which may comprise an annular rib on the plug or socket received in the corresponding annular groove in the bore of the housing.
An electriccal conductor cable 17 is received within the housing 11 and is connected to the terminals of the plug or socket in a manner known in the art.
An external flange 20 of an insert 21, shown in greater detail in FIGS. 5 and 6, is embedded in housing 11. The parts may be joined to each other in a molding operation wherein housing 11 is formed onto insert 21 so that flange 20 is embedded in housing 11. The insert 21 may be formed of a synthetic plastic material and is providedwith an inner shoulder 22. The flange 19 has a plurality of holes 23 which may be spaced equidistantly as shown in FIG. 5. When the housing and insert are molded together, plastic of housing 11 will flow into holes or apertures 23 to lock the parts together.
The other end of the insert 21 is tapered as shown at 24 and has external threads 25 thereon. There are a plurality of axially extending slots 26 in the tapered end of the insertfThree slots are shown but two could be used. Within theouter portion of the tapered end of the insert, there may be provided a plurality of teeth 27 for gripping the outer surface of cable l7.'
A nut 28, which may also be ofa synthetic plastic material, is hand-tightened upon the threads 25 of the insert. Tightening of nut 28 on insert 21 will cause the slotted end portion of insert 21 to grip the outer surface of cable 17 in the area indicated at 30 in FIG. 3 to form a strain relief area. Tightening of nut 28 will close the portion of the insert indicated at 30 to lock and prevent the line cord or cable 17 from pulling out and away from the socket or plug within housing 11.
FIG. 7 shows a modified form wherein housing lIA has flange 20A similar to the prior forms. The wall 21A is straight and has threads 25A thereon.
Thus, it can be seen that the present invention shows an electrical connector which includes an insert having a strain relief area to grip the line cord and within which the insert is secured within the connector with tightening of a nut and is locked in place.
The term plastic is meant to include rubber and other elastomeric material.
It will be understood that changes in various details of construction and arrangement of parts may be made without departing from the spirit of the invention except as defined in the appended claims.
What is claimed is:
1. An electrical connector comprising a housing of plastic material having a bore therethrough for receiving within one end thereof a socket or plug, a plastic tubular insert having an external flange at one end thereof embedded in said housing, said flange having a plurality of openings therein into which the housing plastic enters to lock said housing and insert together, said insert having external threads thereon and adapted to receive an electrical cable therethrough, a nut threaded upon said insert and having an end projection engageable with said housing upon being tightened, the tightening of the nut upon said insert causing said insert to grip a cable therein.
2. An electrical connector as claimed in claim 1 wherein the outside surface of said insert is tapered and said nut engages said tapered wall.
3. An electrical connector as claimed in claim 1 wherein there are a plurality of axial slots in the end of said insert such that tightening of the nut causes the slotted end of the insert to grip the cable.
4. An electrical connector as claimed in claim 3 wherein said insert has a tapered wall gripped by said nut.
5. An electrical connector as claimed in claim 1 wherein there are internal teeth within the end of said insert to grip the outer surface of the cable.
6. An electrical connector as claimed in claim I wherein said housing is of rubber, and said insert and nut are of synthetic plastic material.
7. An electrical connector as claimed in claim 1 and comprising means within said housing for retaining a socket or plug therein. a