More specifically, the invention refers to a pre-mounted tightening elements of the kind that are placed inside an opening or hole placed crosswise in a connector, said connector consisting of a connecting element especially designed for tightening element one or more electrical wires that are entered lengthwise into it by way of one or more tightening elements.

Connectors that allow splices, shunts, or terminations, preferably of metal, with a body that is tubular, generally cylindrical, are well-known. Usually they have one or more holes or bores that cross through the wall of said body in order to hold one or more electrical wires of the same or different diameters running lengthwise inside the connector still in the interior of the connector by way of their respective tightening elements.

On the market there are a wide variety of mechanical screwing connectors that have a wide variety of types of screws to tightening element onto the wiring, entered into one or both ends of the electrical connector, among these, for example, Spanish patents 200502821, 200600568, 200600954, and 200602698, held by the same owner.

In general, the tightening elements are intended to maintain a certain torque on the exterior part of the electrical wire in order to make an electrical connection with said wire. In order to achieve the function of electrically connecting the tightening elements with the wire, the tightening elements are designed so that when the foreseen torque is surpassed, they end up breaking, as there is a choking area, which is preferably ring-shaped, inside them that determines the torque force to be applied to the wire in the interior of the connector, where part of the element breaks.

There are also some tightening elements configured with the additional function of ensuring a degree of waterproofing that is suitable for keeping fluids, such as water, from getting into the connector. This double function of the Tightening elements currently presents technical difficulties, as known tightening elements are made up of a waterproof tightening screw held into the element like an 0-ring, so that when the tightening screw is screwed into the transverse opening of a connector to make an electrical contact with the electrical wire, the waterproofing rubs against the inner walls of the transverse opening and this rubbing force means that when one tries to maximise the waterproofing, the axial pressure on the electrical wiring decreases, so that the electrical contact with said wire is made under conditions of less-than-normal torque transmission.

EP 1 918 595 A1 discloses a controlled shear bolt assembly (1), comprising: a bolt body (10) having, at a free end, a threaded portion from which protrudes a central shank; a head (30) designed to be able to cooperate with a rotary drive tool so that rotary motion is transmitted to the bolt body shank and, consequently, to the threaded portion; and a ring (20) designed to be disposed on the central shank and suitable for ensuring continuity of the male thread with the threaded portion once disposed on the shank; wherein the bolt body presents a single controlled shear zone ensuring the junction of the shank and the threaded portion, with rotation locking means being provided on each ring and the threaded portion to ensure rotation locking of each ring in relation to the threaded portion of the bolt body.

EP 2 375 502 A1 refers to a clamping device with divisible head for an electric connection sleeve. The device (4) has a socket (3) opened at two ends and provided with an external thread and an internal thread, and a screw (2) including a body with a partially threaded lower portion to connect with the internal thread of the socket. The screw body comprises a divisible ring (28) defining an external shoulder and a divisible area (26) separating a body of a screw head. The shoulder is connected with the socket to allow screwing of the socket by an action on the screw head.

US 4 734 061 A deals with a telecommunications terminal block, that provides service wire terminations within cells that are electrically and physically isolated from other cells in the block, and from the environment, thereby effectively preventing corrosion and shorting by eliminating electrical bridging between tip and ring service wire circuits.

EP 1833 117 A2 discloses a screw for electric connectors, the screw being fit to be threadingly engaged into a radial bore of the connector in order to thus clamp and fasten the cable being arranged in the connector, between the head and the threaded portion said screw having an intermediary portion and being thereat provided with an annular necked-down portion and stop next to the head and with an annular necked-down portion next to the threaded portion, said necked-down portions being designed for a clamping torque being predetermined in correspondence with the diameter of the lead for the breakage of the screw in the bore of the connector. The screw has another annular stop next to the necked-down portion being adjacent to the threaded portion, and the screw being provided with two necked-down portion and annular stop pairs incorporates in combination with it an internally and externally threaded bushing, the bushing being thus in a position to have its external thread screwed into the bore of the connector, and the screw being thus in a position to be screwed into the inside of the bushing.

However, none of the documents alone or in combination describes a tightening element having the mentioned double function under optimal conditions.

The main aim of the present invention is to design a tightening element adapted to be mounted inside a opening or hole placed transverse in a connector, within which one or more electrical wires are placed, which on one hand makes optimal electrical contact between the tightening element and the electrical wire, and on the other hand, allows optimal waterproof tightening of the tightening element in the connector.

Another aim of the present invention is to design a tightening elements element that can easily be mass produced with low manufacturing costs, so that later the system can be pre-mounted in a connector.

Another aim of the present invention is to design a pre-mounted tightening element that can easily be assembled by a factory worker inside the transverse opening of a connector.

The present invention consists of a pre-mounted tightening element of the kind placed inside of an opening placed transverse in a connector, as described in claim 1, inside of which one or more electrical wire(s) are placed, this opening having a threaded part at the bottom for the threading to hold the tightening elements still.

The pre-mounted tightening element of the invention is made up of an assembly that comprises:
A means of tightening that is assembly up in such a way that when you act on it, it exercises a torque that is transmitted axially, and when this assembly comes up against the electrical wiring at its lower end, the torque applied, "PI," achieves an optimal electrical contact with said electrical wire; and

Other tightening means that are arranged in such a way that, once this optimal electrical contact is made, when they are acted upon, a torque is transmitted in a radial direction against the lower walls of the opening, and said "P2" torque is suitable for achieving optimal waterproofing of the tightening elements in said opening of the connector.

This particular configuration of the tightening element means that once it is pre-mounted, it can be placed in the opening of a connector by way of two simple, consecutive actions, so that two different functions are fulfilled at the same time: on one hand there is an optimal electrical contact with the electrical wire, and on the other hand, there is optimal waterproof closing of the tightening elements in the opening.

Preferably the transmission of the radial torque of the assembly is made by way of a waterproof joint.

According to a preferred practical version of the present invention, the pre-mounted tightening assembly comprises:

• a tightening element made up of a tightening screw with a head adapted to be screwed into the interior of the opening until its lower end goes all the way against the electrical wire that runs through the interior of the connector and manages to exercise a certain axial torque, "P1," to make optimal electrical contact with the wire, and said tightening screw has a tightening nut; and
• other means of tightening made up of a tightening nut with a head adapted to be screwed onto a waterproof joint until this waterproof joint generates a radial pressure, "p2" that is suitable for making a waterproof closure against the inside walls of the upper part of the opening.

The axial pressure, "p1" of the tightening screw against the electrical wire is achieved by applying a "P1" torque on the head of the tightening screw in a first screwing operation.

The "p2" radial pressure of the waterproofing joint against the inner walls of the opening is achieved by applying a "P2" torque on the head of the tightening nut in a second screwing operation that is transmitted to the waterproofing joint, the lower part of which rests on the connector, so that said torque contracts the waterproof joint axially and thus generates a radial force "P2" against the inner walls of the opening, making a waterproof seal.

The means of holding the tightening nut on the tightening screw can be a threaded part foreseen on the exterior surface of the tightening screw and the corresponding coaxial threaded part of the interior surface of the nut.

Both the tightening screw and the tightening nut include a means of weakening between their respective bodies and heads, so that when the aforementioned heads are screwed all the way in, they break by way of said weakening mechanism.

Optionally, the pre-mounted assembly can include two tightening washers placed above and below the waterproofing joint, made to press on the joint above and below said joint, respectively.

The lower part of the pre-mounted assembly may optionally include an end piece attached to the tightening screw and adapted to make an electrical contact with the wire, this piece being adapted to the material and/or type of each conductor so as to make an optimal electrical contact of metal against metal, due to the great variety of materials (for example, aluminium or copper) and types of wires (solid, flexible, etc.).

The pre-mounted assembly may optionally include an 0-ring in the tightening nut, in order to improve the waterproofing of the tightening assembly.

Other details and features will be shown in the course of the description provided, referring to the drawings that accompany this report, which show the invention, although it is not limited to them, keeping in mind that the versions of the invention can be made in any material, in reference to the composition, as well as the non-critical outside configuration.

Below is a list of the different parts of the invention which are found on the diagrams and which can be located using the following numbers; (10, 10', 10'') tightening element, (11) connector, (12) opening of the connector, (13) electrical wire, (14) known tightening element, (15) threaded part of the opening, (16) inner walls of the opening, (17) tightening screw, (18) head of the tightening screw, (19) tightening nut, (20) head of the tightening nut, (21) waterproofing joint, (22) tightening washers, (23) end piece, (24) O-ring, (25) upper, outer threaded part of the tightening screw, (26) inner threaded part of the nut, (27) lower, outer threaded part of the tightening screw, (28) inner threaded part of the end piece, (29) outer threaded part of the end piece, (30) through-hole of the tightening nut, (31) through-hole of the washer, (32) through-hole of the waterproofing joint, (33) blind hole of the end piece, (35) lower base of the end piece, (36) butting surface of the opening, (37) lower base of the lower washer, (38) O-ring, (39) inner walls of the opening, (39) narrowing in the tightening screw, (40) narrowing in the tightening nut.

In the figures:

• Figure no. 1 shows a frontal view of a conventional tightening element mounted crosswise in a connector, specifically screwed into one of its openings to make an electrical contact with an electrical wire.
• Figure no. 2 shows a side view of the tightening element (10) of the invention.
• Figure no. 3 shows a sectioned side view of A-A' of the Tightening elements (10) of the invention.
• Figure no. 4 shows a view of the tightening element (10) of the invention as seen from above.
• Figure no. 5 shows a view of the tightening element (10) of the invention from below.
• Figure no. 6 shows a frontal view of the tightening element (10) of the invention.
• Figure no. 7 shows the same side view of the tightening element (10) of the invention as figure no. 2, but with the parts separated.
• Figure no. 8 shows the same sectioned side view of the tightening element (10) of the invention as figure no. 3, but with the parts separated.
• Figure no. 9 shows the same frontal view of the tightening element (10) of the invention as figure no. 6, but with the parts separated.
• Figure no. 10 shows a side view of the two tightening elements (10) which are starting to be mounted crosswise in the respective openings (12) of a connector (11).
• Figure no. 11 shows a sectioned frontal view of C-C' of the two tightening elements (10) of figure no. 10.
• Figure no. 12 shows a frontal view of the two tightening elements (10) of figure no. 10.
• Figures no. 13 to 15 show sectioned raised frontal views of the various consecutive positions of the assembly of a tightening element (10, 10', 10'') in the opening (12) of a connector (11).

Figure no. 1 shows a known tightening element with an 0-ring (38) mounted on the outer surface, so that when the tightening element is screwed into the opening (12) of a connector (11) to make an electrical contact with one or more electrical wires (13), this 0-ring (38) rubs against the inner walls (16) of said opening (12), thus making the electrical contact with said wire (13) faulty.

In one of the preferred versions of the invention, and as can be seen in the attached figures no. 2 to 9, the tightening element (10) is made up of a pre-mounted assembly comprising a tightening screw (17) mounted inside a tightening nut (19), a waterproofing joint (21) mounted in the lower part of the tightening nut (19), and two washers (22) mounted above and below the aforementioned waterproofing joint (21).

The tightening screw (17) has a head (18) for the screwing of the same inside the opening by the threaded part (15) until its lower base (35) butts up against an electrical wire(13), having a narrowing (39) between the body and the head (18) as a weakening surface (see figures no. 3 and 8), so that when this head (18) is screwed all the way in, it breaks at this point, as can be seen in figure no. 14. On the other hand, the tightening screw (17) has a screwing part (25) on the outer surface of its body intended to be screwed into the corresponding threaded part (26) of the inside surface of the tightening nut (19), thus joining the tightening nut (19) to the tightening screw (17).

On its part, the tightening nut (19) has a head (20) to screw it against the waterproofing joint (21) placed under the lower base of the nut (19). The waterproofing joint (21), along with both washers (22), mounted above and underneath said waterproofing joint (21), all have an upper diameter that is greater than the diameter of the lower part of the tightening screw (17), so that in the second operation of tightening of the head (20) of the tightening nut (19), the lower washer (20) has its lower base (37) resting on a butting surface (36) of the opening (12) of the connector (11). Therefore, the torque "P2" applied to the head (20) deforms the waterproofing joint (21) (making its height decrease from "e1" to "e2") when it butts against said surface (36), and it necessarily contracts axially and consequently generates a radial force "p2" against the inner walls of the opening, thus achieving a waterproof seal against the outside surface of the body of the tightening screw (17), see figure no. 15.

It can optionally have a end piece (23) attached below to the tightening screw (17) by way of a threaded portion (27) on the lower part of the tightening screw (17) that screws into a corresponding interior threaded portion of the end piece (23), the end piece (23) having the function of making an electrical contact with the wire (13), see figures no. 2 to 9. The end piece (23) has outside threading (29) for screwing in (15).

There can also be an O-ring (24) in the tightening nut (19) to improve the waterproofing of the tightening element (10), see figures no. 2 to 9.

In order to allow the body of the tightening screw (17) to pass through, the tightening nut (19), the waterproofing joint (21), the washers (22) and the end piece (23) have their respective through-holes (30, 31, 32, 33) in an axial direction, (30, 31, 32), except hole (33), which is blind, see figure no. 9.

Figures no. 10 to 12 show a possible version of a connector (11) with two openings (12) in which the respective tightening elements (10) are starting to be mounted.

Figure no. 13 shows the position of the introduction of the tightening element (10) into a opening (12) of a connector (11) in the first assembly operation, figure no. 14 shows the maximum screwing-in position of the tightening element (10) inside the opening (12) of the connector (11) at the end of the first assembly operation in which an optimal axial force is applied downwards, "p1" causing the breaking of the head (18) of the tightening screw, and, lastly, figure no. 15 shows the maximum screwing-in position of the tightening nut (19) on the waterproofing joint (21) in the second assembly operation, causing the breaking of the head (20) of the tightening nut (19) and the generation of an optimal radial force, "p2" in the two directions that makes the closure totally waterproof.