Connector for high pressure environment

[0002] A large number of high pressure connectors are in use to carry electrical power to a water pump that lies at the bottom of a deep (e.g. up to 700 feet) water well. There are other also applications, as well, where an electrical connector must be inserted into a passage of a high pressure connector, that is, a connector that can withstand a high pressure environment such as 2,000 psi. The main wires of the connector are terminated to socket contacts of the connector. In a common prior art type of high pressure connector, a ground wire is soldered or welded to the inside of a stainless steel sleeve which is connected to a grounded housing of the high pressure device. The need to provide a deep drawn stainless steel sleeve for reliability, and to solder or weld the ground wire to the sleeve, results in a considerable cost of the connector. A high pressure connector that could be constructed in a simple design and at lower cost would be of value, especially because a large number of them are sold each year.

[0003] In accordance with one embodiment of the present invention, a connector is provided for use in a high fluid pressure environment for connecting to a device such as a pump motor in the environment, and which can be constructed at low cost. The connector includes a connector body with a frontmost part, a middle part, and a rear part. A nut with an external thread, screws into a threaded hole in a metal casing of the device and presses the body middle part towards a ledge on the device to form a seal thereat. A grounding wire is terminated to a grounding terminal lying in the body rear part and having a finger that projects radially out through the body and that has a finger outer part that is bent to extend forwardly. When the nut is screwed into the device, a smooth inner surface of the nut depresses the finger outer part to establish an electrical connection between the grounding wire and the metal casing of the device.

[0004] In one connector, the frontmost mating part and an elastomeric seal that seals against the ledge, are formed as a single elastomeric part. Main wires extend through the elastomeric part and are encapsulated in potting material of a rearwardly-extending sleeve of the elastomeric part. Rigid plastic is then overmolded around the sleeve part and around the grounding terminal except for the projecting finger part.

[0005] In another embodiment of the invention, the front mating part, middle part and a rear shell part are all molded as a single piece of rigid plastic. A separate elastomeric ring forms a seal against the ledge. After the wires are inserted through the rear shell part, the rear shell part is filled with potting material.

[0006] The novel features of the invention are set forth with particularity in the appended claims. The invention will be best understood from the following description when read in conjunction with the accompanying drawings.

[0007] FIG. 1 is an exploded isometric view of a combination of high pressure device and high pressure connector of the present invention.

[0008] FIG. 2 is a sectional view of the high pressure connector of FIG. 1 lying in the high pressure device but with the nut not yet screwed into place.

[0009] FIG. 3 is a view of a portion of the connector and device of FIG. 2, but with the nut fully screwed into place.

[0010] FIG. 4 is sectional view of a high pressure connector of another embodiment of the invention, and of a portion of the high pressure device of FIG. 1, with the connector installed in the device but the nut not yet screwed into place.

[0011] FIG. 1 illustrates a high pressure connector 10 of the invention which connects conductors 12 of insulated wires 14 to corresponding conductors of an electrically powered high pressure device 20. A very common high pressure device 20 is a motor and pump set that lies at the bottom of a water well that may be up to 700 feet deep for pumping out water from the well. The pressure of water may be very high, and the connector 10 and the walls of a device passage 22 are designed to enable connections to remain sealed despite a high pressure such as up to 2,000 psi. The device 20 includes a metal casing 24 and an inner part 26 to be supplied with electrical power. The device passage includes an outermost largely threaded part 30 and a smaller diameter inner part 32. Two or three pin contacts 34 lie in the inner passage part, depending on the type of power that is supplied. It is noted that the device passage 22 has a polarizing recess 40 that receives a protuberance 42 on the connector to assure that the connector is inserted in the proper rotational orientation about an axis 44. In addition to the two or three power-carrying contacts 12, a grounding wire 50 is provided with a grounding conductor 52. In the present invention, the grounding conductor 52 is connected to a ground terminal with a finger outer part 54 that engages an externally threaded nut 60 to provide a ground connection to the metal threaded outer portion 30 of the device recess.

[0012] FIG. 2 shows the finger outer part 54 is part of a grounding terminal 62 which is connected to the front F end of the ground connector 52. The nut 60 has a smooth nut inner surface 64 that engages the finger outer part 54 when the nut is pushed forwardly and then screwed into the threaded portion 30 of the device metal casing 24. The finger outer part 54 is preferably resilient, and remains in firm contact with the nut inner surface when the nut is fully screwed into place. The finger has a circumferential (around axis 44) width that is a plurality of times its radial thickness to avoid circumferential deflection by the nut inner surface. FIG. 3 shows the nut 60 fully screwed into place and causing an elastomeric seal portion 70 to seal against a ledge 72 that extends between the larger diameter passage portion 30 in the metal casing, and a smaller diameter inner passage portion 74 of the device passage.

[0013] FIG. 2 shows that the connector includes a body 80 with a frontmost mating body part 82, a middle body part 84 lying rearward R of the mating part, and a rear body part 86 that extends rearward of the middle body part. The mating body part 82 fits in the device passage front end 74 and has a plurality of contact-holding bores 90 that holds socket contacts 92. The socket contacts receive the pin contacts 34 of the device. The middle body part 84 lies in the device passage outer, or rear portion 30, which is of larger diameter than the front portion 74. The rear body part 86 projects rearwardly out of the device passage. The middle body part forms an annular forwardly-facing shoulder 100. In the embodiment of FIG. 2, the shoulder 100 directly engages the ledge 72. The middle body part also forms an annular rearwardly-facing shoulder 102, with a metal washer 104 lying on the shoulder 102.

[0014] When the nut 60 is screwed tightly into place, as shown in FIG. 3, a nut front end 110 presses forwardly against the metal washer 104, thereby compressing the elastomeric part 70 which presses against the ledge 72 to form a seal at the ledge.

[0015] FIG. 2 shows that the forward mating body part 82 and the elastomeric seal 70 are molded integrally as a single member 120 of elastomeric material. The member 120 also includes a sleeve portion 122 that extends rearwardly of the elastomeric seal 70 and of the forward matting body part 82. To construct the connector of FIG. 2, applicant first forms the body 120 by molding, and then installs main wire-end-contact assemblies 130 in place as shown. Each assembly 130 includes a main wire 14 whose conductor at 12 is fixed to the rear end of a socket contact 92, as by crimping and/or soldering. The socket contact and a front end of the wire 14, including the wire insulation 132, projects into the contact-holding bore 90 in the forward mating body part. After all two or three main contact assemblies 130 are installed, a quantity 140 of potting material is poured into the sleeve portion 122 to largely fill it. The potting material 140 is a material such as epoxy in a fluid state that cures or otherwise hardens, and serves to form a seal that prevents moisture from entering the contact-holding bore 90 by flowing forwardly around a main wire 14.

[0016] After the contact assemblies 130 are installed, the ground wire 50 with the ground terminal 62 fixed to the ground wire conductor 52, are placed in a mold, in the position shown. Then, a rigid engineering plastic is injected into the mold to fill it to the configuration shown in FIG. 2. The sleeve portion 122 of the elastomeric molded part 120 has grooves 150 that lock it to the rigid engineering plastic that is molded around it and the rear end of the quantity 140 of potting material. The rigid engineering plastic has a rear plastic part 152 that is solid, in that the rigid plastic extends across the entire diameter of the body except for the wires 14 and the ground wires and grounding terminal.

[0017] Applicant is able to use an epoxy potting material 140 that cures in about one-half hour (in an oven) instead of requiring a special epoxy that can withstand a high pressure such a 2,000 psi and which requires more time to cure.

[0018] An elastomeric material may be defined as one with a Young's modulus of elasticity of no more than about 50,000 psi. A rigid engineering plastic may be defined as one having a Young's modules of elasticity greater than 100,000 psi, and preferably more than 200,000 psi.

[0019] FIG. 4 illustrates an electrical connector 200 of another embodiment of the invention. The connector 200 includes the main wire-and-contact assemblies 130 that each includes a socket contact 92 attached to a conductor 12 of a main wire 14. The connector 200 also includes a ground terminal 62 that is attached to a conductor 52 of a ground wire 50 and that has a finger 53A with a finger outer part 54A. The connector also includes a nut 60 whose nut front end 110 can engage a metal washer 104.

[0020] The connector 200 includes a connector body 202 with a frontmost mating body part 204 that fits in the device passage inner part 74, a middle body part 206 lying in the device passage outer part 30, and a rear body part 210 that extends reward of the middle body part and that projects out of the device passage 22. The three body parts 204, 206 and 210 are integrally formed as a separate member 212 of rigid engineering plastic. An elastomeric seal part 214 that forms a seal against ledge 72, is a separate elastomeric washer.

[0021] The combination of ground wire 50 with the ground terminal 62 attached, is lowered into the rearwardly-opening interior 220 of the shell-shaped rear body part 210. The finger 53A is inserted through a hole 222 in the rear body part or shell part 210. The hole 222 can be formed during molding of the shell part 210 with the rest of the member 212, or can be formed as by drilling, after molding. The finger 53A of the ground terminal can slide radially outward through the hole 222. With the main wire-and-contact assemblies 130 installed and the ground wire 50 with ground terminal 62 placed in the shell part 210, the shell part is filled with a potting material 224 such as an epoxy, and the epoxy is cured. An epoxy that can withstand high pressure such as 2,000 psi is used, and it may require more than an hour to cure.

[0022] After the epoxy has cured, the projecting finger portion 54A is bent radially inwardly, as to the position shown in solid lines in FIG. 4. The projecting finger portion will be deflected further radially inwardly by the nut 60.

[0023] Applicant prefers the construction of FIG. 4, in that it results in a lower cost connector. That is, only a single member 210 must be injection molded. Although it takes longer for the potting material 224 to cure, the use of a single molded member results in an overall lower cost.

[0024] Thus, the invention provides a high pressure connector which can be constructed at moderate cost. The connector includes a connector body with a front mating part that fits in a small diameter device passage inner portion, a middle body part that fits in a larger device outer passage portion, and a rear body part that projects rearwardly out of the device passage. The middle body part forms a forwardly-facing shoulder that can be pushed forward by a threaded nut to compress an elastomeric seal against a ledge of the device. A ground wire is connected to a metal casing of the device through a ground terminal that has a finger projecting outside the rear body part and bent to extend largely forwardly. As the nut is moved forwardly and screwed into the metal casing of the device, it engages the bent projecting finger portion, to establish electrical connection of the ground wire to the casing through the finger and nut. One connector forms the body of a first molded elastomeric part that forms the front body part and the elastomeric seal at the front of the middle body part. That embodiment of the invention also includes an overmolded rigid engineering plastic that is overmolded around a rear of the molded elastomeric part and against potting material in the molded elastomeric part. In another embodiment of the invention, the body is formed of a single molded rigid plastic member, with an elastomeric seal placed at the rear end of the front body part to seal against the ledge of the device. In that case, the rear body part is in the form of a shell that is filled with potting material.

[0025] Although particular embodiments of the invention have been described and illustrated herein, it is recognized that modifications and variations may readily occur to those skilled in the art, and consequently, it is intended that the claims be interpreted to cover such modifications and equivalents.