ELECTRICAL CONNECTOR

Abstract: An electrical connector (10) in which an electrical time dalay circuit means (64) is mounted within a connector (10) to allow a remote location of said time delay circuit means. The connector (10) also includes setting recess means (28A, 28B) within the connector (10) to produce a setting action between electrical leads (A, B) and a C-clip terminal (18) having angled tips (20A, 20B) which wedge against an inserted lead (A, B).

Description: ELECTRICAL CONNECTOR Background of the Invention This invention concerns electrical connectors. In one form of the invention the connector incorporates time delay circuit means. Such an arrangement has particular application in detonating devices such as widely used in exploration, construction and mining. The invention also has uses in domestic and commercial areas. U.S. patent No 4,952,167 discloses a highly reliable electrical connector. In one form, the present invention provides an improved electrical connector. In the connector of U.S. patent No 4,952,167 the lead wires are inserted into holes at either end of the connector and pressed between spring metal clip ends of a C-shaped clip and the inside facing surface of a wall of the connector housing. Upon pulling of each wire back, a groove in the respective end of the C-clip bites through the insulated jacket of the wire and deflects the end back to be set in the wall surface to establish an electrical connection between the wires through the C-clip. This design works very well but there is a need to more reliably maintain the set condition when pushing forces are exerted on the inserted wires, as there is a tendency to loosen the connection under that condition. In certain industries, including the mining industry, there is often a need for a series of detonating devices to be set off at slightly different times, with a precisely controlled time delay between success of detonations being desirable for various reasons. The earlier methods of creating a delay involving the use of variable length internal pyrotechnic fuses has given way to the use of electrical circuits which electronically delay the application of an electric pulse to the fuzehead of detonator. This development eliminated the need to stack various delay time detonators. Reference is made to U.S. Patent No 4,646,640 issued on March 3, 1987 for a "Process and Apparatus for Chronologically Staggered Initiation of Electronic Explosive Devices", and U.S. Patent No 4,324,182 issued on April 13, 1982 for "Apparatus and Method for Selectively Activating Plural Electrical Loads at Predetermined Relative Tunes" , for examples of such electrical delay circuits. Heretofore, such circuits have taken the form of "chip" circuits built into each explosive device. A design in which the circuit is built into the explosive device has disadvantages, i.e., the cost of manufacture is increased by the degree of care and precautions necessitated when dealing with pyrotechnic devices and additionally, the small size casing which houses the pyrotechnic device limits the size of the circuit chips used. Summary of the Invention The present invention comprises an improved electrical connector of the type described in U.S. patent 4,952,167, in which improvement a contained "set" space is provided adjacent each inwardly inclined end of the C-clip. The lead end enters through an entrance hole, of a respective end cap, at a point adjacent the upper region of the interior of the connector housing, aligned with the upper most edge of the C- clip end with which it is to be mated. After the lead end passes between the C-clip end and the housing cavity inner surface, it is pulled back, causing the insulating jacket of the wire lead to be sliced through, and continued tension pulls the clip end outwardly into the set space, where the lead and clip ends are then wedged securely. This results in a secure electrical connection between the lead end and clip end resisting both pulling and pushing forces exerted on the set wire lead. Fittings are fit into either end of the housing which define in part the set space, each plug having an offset opening opposite a respective clip end so as to direct a respective electrical lead to a respective clip end. The housing is preferably sealed as by sonic welding of the interfit housing parts and filled with a sealing substance to protect the delay circuit as well as the electrical connections from the deleterious effects of moisture" and other ambient conditions. The connector also has a capability of connecting leads from a detonating machine to each detonating device which incorporates a built-in circuit chip consisting of a time delay circuit. The chip is electrically and mechanically joined to opposite pairs of clip ends to form an integral clip assembly, which assembly is fit within an oblong space within the connector housing. The advantage of such an electrical connector having a built- in electrical delay circuit is to lower the costs of manu¬ facture and to allow the possibility of stocking only one pyrotechnic blasting cap for all applications. Description of the Drawings FIGURE 1 is a side view of a single lead pair ver'sion of the electrical connector according to the present invention. FIGURE 2 is a longitudinal sectional enlarged view of the connector shown in FIGURE 1 with an electrical lead inserted in either end, one of the leads pulled to the set condition. FIGURE 3 is a perspective view of the C-clip installed in the housing of the connector of FIGURES 1 and 2. FIGURE 4 is a perspective view of a double lead pair version of the connector according to the present invention with connected detonating cap and detonating machine. FIGURE 5 is a plan sectional view of the double lead pair version of the connector shown in FIGURE 4 with connected detonating cap and detonating machine. FIGURE 6 is a lengthwise sectional view through the connector shown in FIGURES 4 and 5. FIGURE 7 is a transverse sectional view through the connector shown in FIGURES 4 and 5. FIGURE 8 is a perspective view of the double clip and delay circuit chip assembly incorporated in the connector shown in FIGURES 4-6. Detailed Description In the following detailed description, certain specific terminology will be employed for the sake of clarity and a particular embodiment is described with reference to the drawings. However, it is to be understood that the same is not intended to be limiting and should not be so construed inasmuch as the invention is capable of taking many forms and variations within the scope of the appended claims. Referring to FIGURE 1, the electrical connector 10 according to the present invention, is adapted to electrically connect a pair of electrical leads securely together, end-to-end, without the use of crimping tools. The connector 10 includes a housing 12 defining a rectangularly shaped internal cavity 14, the housing preferably molded of a suitable rigid dielectric material, such as a polypropylene plastic. The housing 12 is elongated and either end receives a plug 14A, 14B configured to close off each end thereof secured and sealed at assembly as by sonic welding or with a suitable adhesive. Each plug 14A, 14B is formed with a pair of conically tapered round bores 16A, 16B, each adapted to receive the end of a respective electrical lead A,B. Each bore 16A, 16B is located offset vertically from the center to be located opposite the upper wall of the housing cavity 14. The connector housing cavity 11 receives a C-clip assembly 18 sized to be slidably fit into the rectangularly shaped cavity 14 formed therein. C-clip 18 defines a pair of terminal means for selective connection to electrical leads, comprised of a pair of clip ends 20A, 20B comprising the terminal means, inwardly angled from straight section 21. The ends 20A, 20B and straight section 21 are constructed of a formed flat strip of electrically conductive resilient material, such as spring steel, brass, or beryllium copper. The C-clip ends 20A, 20B are inclined inwardly towards each other to form a ramp surface facing a respective guide hole 16 at either end. The geometry of the C-clip ends 20A, 20B is different from that disclosed in United States patent specification No 4,952,167, in that the tips 22A, 22B are bent to decrease the obtuse angle and increase the acute angle otherwise existing with respect to confining surfaces of the housing 14. This then results in a relatively steep angle between the tip and the confining surface of the housing cavity 14. The C-clip ends 20A, 20B are deflected by being assembled into the cavity 14 so that each tip 22A, 22B exerts some pressure against the facing cavity surface. Thus as a lead 24 or 26 is advanced into the cavity 14 through a bore 16, it encounters the facing surface of the adjacent C-clip end 20A, 20B, deflecting the same to enable advancing of the lead end between the tip 22A or 22B of a respective C-clip 20A, 20B respectively and the surface of the housing cavity 14. The intended electrical connection is established by a slotted contact recesses 26A, 26B formed in the outer edge of the respective C-clip tip 22A, 22B. The width of each of the slotted recesses is the same as the thickness of the lead conductor such as to cause the insulating jacket to be sliced through as the lead 28, 30 is pulled back. Various alternate geometries are possible for the contact recesses 26A, 26B, such as a sharp vee shape geometry, or rounded or serrated central openings inward from inclined entry edges guiding the leads into the opening. A strong self gripping action between the tip 22A or 22B and the electrical lead A or B is established, causing slicing through the insulation and seating in the recess 26A or 26B. Upon continued pulling pressure on the lead A or B, the tip 22A or 22B is pulled outwardly to enter a set recess 28A or 28B defined at either end of the connector by a shoulder 30A, 30B in the upper surface of the cavity 14, and a contoured inner surface of each of the plugs 14A, 14B. The strong self gripping effect enables each end 20A, 20B to be moved outwardly by pulling forces applied to the lead A or B to wedge the same within the inner surfaces of recess 28A, 28B with the respective lead A or B. This setting action anchors the respective C-clip end 20A, 20B to prevent any loosening after seating of the lead A or B. The C-clip assembly 18 must be securely anchored to resist shifting in the housing cavity 14 during setting of the leads, and thus molded protrusions 32A, 32B, and central protrusion 33 projecting up from lower housing wall are received in openings in the straight section 21 for this purpose. In order to insure a waterproof connection, the housing cavity 11 is preferably completely filled with a dielectric gel or grease such as silicone, a small proportion of which is expelled upon insertion of a wire, insuring continued complete occlusion of that space, and waterproofing protection. The double lead version connector 34 includes a housing 40 subdivided by a central partition 42 into a pair of internal cavities 44, 46, each rectangular in shape and elongated so as to be capable of receiving a respective C-clip 48, 50. A doubled plug end cap 52, 54 is received in either open end of the housing 40, and sonic welded to secure and seal the same to the housing 40. Tapered entrance bores 56 are formed in each plug of both end caps 52, 54 to receive an inserted lead Al A2, Bl, or B4, directing the same to a slot 60 in respective end 58A, 58B, 59A, 59B of the C-clip 48 or 50. Each of the C-clips 48 and 50 are configured similarly to the single lead pair version described above, except that the respective ends 58A, 58B and 59A, 59B are not directly electrically connected, having an intervening central gap 62 therebetween. This gap is bridged by a time delay circuit chip 64 overlying adjacent ends of straight sections 66A, 66B and 67A, 67B associated with C-clip ends 58A, 58B and 59A, 59B. The circuit chip 64 is mechanically and electrically connected to the straight sections 66A, 66B, and 67A, 67B as by soldered tabs shown, so as to create a unitary assembly and a time delay circuit. A housing cover 70 creates an opening in the top of the housing 40 before assembly, enabling the C-clip and chip assembly to be installed in the cavities 44, 46, the cover then sealed as by sonic welding. The partition 42 is cut away to accommodate the clip 64, with a web 72 integral with the cover 70 fit in the gap between sections of the partition 42A, 42B to separate the cavities 44, 46. FIGURE 4 shows that the invention may take the form of a double lead pair connector 34 able to connect each of the two lead pairs Al, A2, Bl, B2 required in each detonation circuit between a firing control unit 36 and a detonator 38. The chip 64 carries a suitable time delay circuit as for example the circuit described in the above referenced U.S. patent 4,324,182. Some additional required elements such as a power supply capacitor 74 may be mounted to the chip 64 as described in the aforementioned U.S. patent. The circuit on the chip 60 is designed to introduce a programmable delay of the time of transmission of a firing electrical current pulse from a firing control unit 70 to an explosive detonator cap 68 shown in FIGURE 4. A firing control unit 36 is connected to each of the explosive detonator devices 38 and connectors 34 in a given array and controls the transmission of programming and firing signals, all as described in U.S. Patent No 4,324,182. Accordingly, the time delay circuit may be separated from the detonator itself to make manufacture easier, and to eliminate the constraints imposed by incorporation into a pyrotechnic device described above, as well as to obviate the need for stocking variety of detonators. The invention has been described by way of example only with reference to the delay circuit being used in association with detonators, but it should be appreciated that the invention has equal application in other areas, such as domestic, manufacturing, commercial activities.

Claims: CLAIMS : 1. An electrical connector comprising: a connector housing having an internal cavity formed therein; a plurality of terminal means within said housing comprising means for selectively establishing an electrical connection to each of a pair of electrical leads entering said housing; time delay circuit means located within said housing and being electrically connected to both of said terminal means, whereby said time delay circuit means is electrically connected along the circuit defined by said leads. 2. An electrical connector as claimed in claim 1, wherein said time delay circuit means includes a time delay circuit chip. 3. An electrical connector as claimed in claim 1 or claim 2, wherein said terminal means includes clip ends of a conductive material adapted to grip a conductor within said housing cavity, said time delay circuit means being mechanically and/or electrically connected to said clip ends, to together form a unitary assembly and electrically connect said clip ends into said time delay circuit. 4. An electrical connector as claimed in claim 3, wherein said terminal means including clip ends, is sealed within said housing cavity. 5. An electrical connector for establishing a splice connection between electrical leads having an insulating jacket and a conductor core, including: a hollow elongate connector body of an electrically insulating material, having interior walls defining a cavity therein and having an opening at each end; a C-clip of a strip of resilient, conductive material being disposed in said cavity, said C-clip having a pair of ends, each end extending from an elongate straight portion lying against an inner surface of one wall of said cavity of said connector body and extending lengthwise within said cavity, each of said ends being inclined towards the other and away from a respective adjacent opening of said connector body, each end having a tip lying at a point closely adjacent another inside surface of another wall of said cavity of said connector body, opposite the inside surface of said first mentioned wall, said tips being bent to decrease the obtuse angle and increase the acute angle otherwise existing relative to confining surfaces of said cavity; a contact recess formed into an edge of each tip, comprising a slot having closely spaced opposite edges adapted to slice through said insulating jacket and contact said conductor core as an electrical lead is pulled back after insertion into said connector body, to be seated within a contact recess, whereby an electrical lead may be inserted at either end to engage and deflect a respective C-clip end and move past said terminal edge, to thereby be gripped against pull-out by the edges of said contact recess spliced into said insulating jacket. 6. An electrical connector as claimed in claim 5, wherein plug means are adapted to fit into each end of said cavity, said plug means being provided with means opening and extending into said cavity; a set recess being defined between each of said plug means and including a step in inside surface(s) located outwardly of each C-clip end tip, prior to pulling out of said C-clip tip, creating an increased space outside of said tips and adjacent said respective plugs, so as to allow a respective tip to move into said increased space as said C-clip end is pulled out. whereby said tip and electrical lead may be wedged into said set recess to secure said connection. 7. An electrical connector as claimed in claim 6, wherein each of said tips is inclined with respect to the remaining C-clip end portion to increase the obtuse angle between said inside surface and said tip. 8. An electrical connector as claimed in claim 6, wherein each of said plugs has a shaped contour facing respective C- clip ends, to receive said C-clip ends thereagainst upon setting of said electrical lead. 9. An electrical connector as claimed in claim 6, wherein said C-clip is fixed in said housing cavity against lengthwise movement therein.

Inventors: HERTELENDY CHRIS, WALDOCK KEVIN HUNTER, HERTELENDY, CHRIS, WALDOCK, KEVIN, HUNTER
Applicants: WALDOCK KEVIN HUNTER, WALDOCK, KEVIN, HUNTER
Application year: 1992
Main classification: F42C11
IPC codes: F42D1, H01R4