Vice-type terminal block for interconnecting two thimbles and associated connection

A vice-type terminal block for electrically connecting a pair of lugs by clamping them together. Each lug includes a barrel extending along an axis and a radially extending flange connected to the barrel. The flange has, on the opposite side to where the barrel is located, an electrical contact surface normal to the axis. The vice-type terminal block includes two opposing plates and a clamping system. Each plate includes a slot for receiving one of the lugs such that the flange of the lug is on one side of the plate, whereas the barrel is on the other side. The pair of lugs are supported such that their electrical contact surfaces face one another and are aligned.

This is a National Stage application of PCT international application PCT/FR2016/063314, filed Dec. 9, 2016 which claims the priority of French Patent Application No. 15 62595 entitled “VICE-TYPE TERMINAL BLOCK FOR INTERCONNECTING TWO THIMBLES AND ASSOCIATED CONNECTION”, FILED Dec. 17, 2015, both of which are incorporated herein by reference in their entirety.

TECHNICAL FIELD

The invention relates to the electrical terminations or connectors for power connections. More particularly, the invention relates to a vice-type terminal block for clamping a lug of a power cable to a second lug to electrically connect them together.

PRIOR ART

In the field of aircraft construction, it is increasingly common for aeroplanes to be built in pre-assembled segments, which are subsequently quickly connected on the assembly line for faster manufacture. These segments are already pre-fitted with wiring, pipework and structural connections, which simply require connection to those of the following segments.

Power supply cables are connected to other cables or electrical elements using electrical lugs provided at the end of each cable. Tubular lugs are often used, i.e. lugs having a tubular barrel for connection to the cable and a tongue substantially parallel to the barrel with a central hole. Such a conventional lug is connected to the other elements via a terminal block comprising a stud on which the tongue of the lug is positioned and a nut tightened on the stud. In order to connect two cables in a straight line, the lugs of two cables are positioned either on two different studs electrically connected to the same terminal block, or on the same stud, then secured together.

This can become problematic when the cable is twisted. Twisting is highly likely when routing a cable in a structure such as a segment of an aircraft. Typically, the lug must be oriented about the cable so that the hole of the tongue is aligned with the stud of the terminal block. For power supply cables of high stiffness (for example, as a result of a short length or a large cable cross-section), the change in orientation, which may need to be up to 180° to allow their connection, is particularly difficult.

Moreover, the connections described hereinabove entail the non-negligible risk of causing to foreign object damage (FOD). More particularly, a nut that comes loose, for example, can easily come away from the electrical connection and cause FOD.

As a result, a new type of lug has been developed to connect two cables which does not require any change in orientation. This lug is of the type comprising a barrel extending along an axis in a substantially centred manner for connection to an electrical cable and a flange connected to said barrel and extending radially relative to said barrel, said flange having, on the opposite side to where said barrel is located, an electrical contact surface substantially normal to said axis, intended to be placed in electrical contact with an electrical element.

A cable with such a lug can be electrically connected to a second cable having such a lug by placing the electrical contact surfaces facing one another. No axial orientation is required, given that the lugs have a frontal electrical contact surface, i.e. in the axial direction.

However, an adapted terminal block is required to clamp and maintain said two lugs in this position to ensure a good, reliable contact.

DESCRIPTION OF THE INVENTION

The purpose of this invention is therefore to propose a terminal block that is suitable for receiving two lugs of the type described hereinabove, such that their electrical contact surfaces face one another and are substantially aligned when the terminal block clamps the lugs with one another in order to connect two cables. Another purpose of the invention is to provide a terminal block that is easy to use, and that has a significantly reduced likelihood of being the cause of FOD or of being subjected to FOD.

This invention thus proposes a vice-type terminal block for electrically connecting a pair of lugs by clamping them together, each lug being of the type comprising a barrel extending along an axis in a substantially centred manner, and a flange connected to said barrel and extending radially relative to said barrel, said flange having, on the opposite side to where said barrel is located, an electrical contact surface substantially normal to said axis, the vice-type terminal block comprising two opposing plates and a clamping system for moving the two plates towards one another, characterised in that each plate comprises a slot for receiving one of said lugs such that the flange of the lug is substantially on one side of the plate and between the two opposing plates, whereas the barrel is substantially on the other side of the plate, the vice-type terminal block further comprising a means for supporting the pair of lugs such that their electrical contact surfaces face one another and are substantially aligned.

Preferably, said means for supporting the lugs comprises the bottom of at least one slot which is adapted to support the barrel of at least one lug.

Preferably, said means for supporting the lugs comprises a means adapted to support the flange of at least one lug.

Advantageously, each plate comprises three slots thereby allowing three pairs of lugs to be connected.

Preferably, each slot extends from an edge of the respective plate.

More preferably, the clamping system comprises at least one protruding portion that protrudes normally to the surface of the first plate, and at least one through hole located on the second plate, the protruding portion extending through the hole and comprising a cam mounted on the protruding portion.

Advantageously, the two plates comprise the counterbores adapted to receive the flanges of the lugs.

Preferably, the vice-type terminal block further comprises a protective cover.

This invention further proposes a connection comprising a vice-type terminal block such as that defined hereinabove, characterised in that the connection further comprises two lugs of the type comprising a barrel extending along an axis in a substantially centred manner, and a flange connected to said barrel and extending radially relative to said barrel, said flange having, on the opposite side to where said barrel is located, an electrical contact surface substantially normal to said axis, the lugs being positioned such that their electrical contact surfaces face one another, the vice-type terminal block clamping the flanges of said two lugs against one another in order to connect said lugs and maintain their position.

In all of these figures, identical references may denote identical or similar elements. Moreover, the different parts shown in the figures are not necessarily displayed according to a uniform scale in order to make the figures easier to read.

DETAILED DESCRIPTION OF A SPECIFIC EMBODIMENT

FIG. 1shows a vice-type terminal block50according to a first embodiment of the invention for pressing two lugs10(FIG. 3) against one another. In this case, the vice-type terminal block50is adapted to receive and connect three pairs of lugs10, however, it can be designed to connect more or fewer cables.

The vice-type terminal block50comprises two substantially rectangular, opposing plates51,52that can move towards one another in order to clamp the lugs10. A first plate51is intended to be fixed, and is referred to herein as a “fixed plate”, whereas the second plate52is intended to be moved relative to the first plate51, and is thus referred to herein as a “mobile plate”. The two plates51,52are of the same size, are substantially flat, have about the same thickness, and are preferably made of an insulating material (electrical non-conductor).

The fixed plate51has three slots61that descend vertically from the top edge in an inwards direction relative to the plate51for receiving lugs10of the cables25. It further comprises four protruding portions54protruding from the surface of the fixed plate51facing the mobile plate52. The protruding portions54extend substantially normally to the surface of the fixed plate51, and are each U-shaped, more specifically in the shape of a round bar outlining a U with the two branches of the U being connected to the fixed plate51and the base of the U being located away from the fixed plate. These protruding portions54are intended to support cams56and at the same time guide the movement of the mobile plate52.

Two mountings53with a central hole are attached to the fixed plate (one on the left and one on the right), which mountings53allow connection in a fixed manner to a structure, for example on a stiffener in a segment of an aeroplane.

The mobile plate52in turn has three slots62that descend vertically from the top edge in an inwards direction relative to the plate for receiving lugs10of the cables, which three slots62correspond respectively to those of the fixed plate51. Moreover, the mobile plate52is also provided with four through holes55which correspond to the protruding portions54of the fixed plate51. The two plates51,52are arranged in a substantially parallel manner to one another and near one another, with the protruding portions54of the fixed plate51extending through the through holes55of the mobile plate52.

Moreover, the vice-type terminal block50is provided with a clamping system for clamping the two plates51,52of the vice-type terminal block50against one another. In particular, each of the terminations of the protruding portions54, i.e. the bases of the U, are provided with a cam56. The cams56are mounted so as to allow their rotation about the base of the U and thus allow the clamping or release of the two plates51,52. They comprise a handle that allows their manual rotation between the open position (horizontal) and the locked position (downwards). The cams56pass beyond their maximum point just before reaching the locked position. This helps the clamping system to remain in position once locked.

In order to reduce to likelihood of being the cause of FOD, the cams56are made in one piece. Preferably, they are mounted on the base of the U using additive manufacturing or3D printing methods. The entire vice-type terminal block50can also be produced using these methods. Of course, other clamping means for the vice-type terminal block50can be envisaged instead of this cam-based clamping system.

When the vice-type terminal block50is clamped by its cams56, the mobile plate52moves in translation, pushed by the cams56and guided by the protruding portions54, towards the fixed plate51, and the two plates51,52press against one another to clamp, with a uniform force, the flanges12of the lugs10received in the vice-type terminal block50against one another.

The invention shall be understood more clearly with reference to the connection shown inFIG. 2, comprising a vice-type terminal block50with three identical pairs of lugs10. Each of the lugs10is crimped to its respective cable25, and the three pairs are intended to be connected to form three complete cables (corresponding to three-phase electricity). The lugs10are made of metal, for example aluminium or copper, however can be provided with a coating surrounding the entire exterior of the lug with the exception of the electrical contact surface13which, in turn, is preferably treated (by nickel plating or stripping) to guarantee minimum contact resistance.

The two lugs10of each pair are positioned in the vice-type terminal block50with their electrical contact surfaces13facing one another in order to electrically connect their cables in a straight line, for example to connect a power cable of a segment of an aeroplane with a cable of a following segment.

The vice-type terminal block50comprises three pairs of opposing slots61,62, i.e. three slots per plate. Each slot61,62descends vertically from the top edge of its plate51,52to the same depth, about midway along the height of the plate51,52, and ends with a bottom. When the lugs10are inserted into their respective slots61,62, the barrel11of each lug10abuts against the bottom of the slot61,62, and the flange12of the lug10is substantially located on the side of the plate51,52facing the opposing plate52,51(i.e. between the two plates), whereas the barrel11is located substantially on the other side of the plate51,52.

Since the slots61,62are directly opposite, and since the bases are at the same level, each pair of opposing lugs10has both their electrical contact surfaces13essentially aligned facing one another.

The vice-type terminal block50of the invention thus allows two lugs10of the type described to be easily connected, without requiring any change to the orientation of the lugs10.

FIG. 3shows a more detailed view of the same lug10as those inserted in the vice-type terminal block50of the connection shown inFIG. 2, which lug10has a shape as described, however which further comprises other additional characteristics, giving it the shape generally preferred for use with the vice-type terminal block50. In particular, the flange12extends radially relative to said barrel11such that it is substantially centred on said axis, i.e. such that the geometric centre of the flange12(viewed from the direction of the axis) is on the axis. Moreover, it is circular, as well as its electrical contact surface13. Furthermore, the barrel11of the lug10is substantially cylindrical.

When two such lugs10are inserted into opposing slots61,62of the vice-type terminal block50, the barrel11of each lug10abuts against the bottom of the slot61,62and will be supported such that the two electrical contact surfaces13will be aligned facing and fully overlapping one another. Since the flange12has a frontal surface, no specific axial orientation needs to be followed and the lugs10can be reliably connected without requiring any change in the orientation of the lug10about the axis of the barrel or of the cable25. Moreover, since the flanges12are circular, the overlapping surface area between the flanges12of said two lugs10when they are facing one another will remain the same, as will the electric conductivity (the current density A/mm2capable of being carried for a given temperature rise), regardless of the relative axial orientation of the two lugs10.

The shape of the barrel11of the lug10plays a role in ensuring that the flanges12align with one another. Since the barrel11is cylindrical, the central axis of the barrel will stay in the same position, regardless of the axial orientation of the barrel11when it is positioned at the bottom of the slot61,62. The flanges12of the lugs10facing one another can thus be easily aligned in a coaxial manner and with full overlap by placing the two barrels11at the bottom of the slots61,62, where they will be coaxial.

Of course, the vice-type terminal block50can receive and connect lugs where the shape of the flange is not circular, for example square. However, the overlap between the electrical contact surfaces of two such identical lugs presented facing one another, even if the flanges are centred and aligned on the same axis, will change depending on the relative angular orientation of the two lugs. The change in overlapping surface area involves a change in current carrying capacity and in the resistance of the connection. As a result, lugs10with flanges12that are circular in shape are generally preferred for use with said vice-type terminal block50.

In order to support a pair of lugs10such that their electrical contact surfaces13are facing one another and substantially aligned, the vice-type terminal block50can be designed to support the flanges12of the lugs instead of the barrel11. This may be particularly suitable when the flanges12are round.

In a variant, the vice-type terminal block can be designed to receive the lugs with a flange that is not flat, but may comprise, for example, a rounded surface on the side opposite the electrical contact surface to reinforce it.

It can be observed that there is only a small space between the two plates51,52in the open position. This not only helps to maintain the lugs10inserted into the vice-type terminal block50in position, but also prevents a fitter from trying to connect two cables of insufficient length by forcing them together. Moreover, since the plates51,52move in translation when the vice-type terminal block50is clamped, the forces to which the cables are subjected are mainly axial and the lugs10are therefore less likely to leave their slot61,62. As a result, the lugs10of the cables can be inserted in the right position facing one another, then the vice-type terminal block50can be clamped.

Once all of the lugs10of the cables to be connected are inserted, the vice-type terminal block50is clamped by its cam-based clamping system, the electrical contact surfaces13of the two lugs10press against one another to guarantee conductivity with low electrical resistance. The clamping also helps to withstand static loads and vibratory effects, by preventing any relative movement between the lugs10, and between the lugs10and the vice-type terminal block50.

FIG. 4shows the same connection100as that inFIG. 2, with the cams56in the locked position in which they clamp the two plates51,52against one another and thus the flanges12of the lugs10against one another. In order to properly secure the cams56and prevent them from becoming unlocked (for example as a result of vibrations or impacts), a cotter pin59is used. The cotter pin59passes through the holes provided on the handles of the cams and the attachment points on the vice-type terminal block50in an interleaved manner, and is then in turn secured such that it does not come undone.

A protective cover70is used to reduce the risk of being affected by FOD. It comprises a horizontal rectangular plate71, a central plate72extending in the direction of the length of the rectangular plate71and downwards, intended to be clamped by the vice-type terminal block50, and several side plates73extending in the direction of the width of the horizontal, rectangular plate71and downwards. The protective cover70is used, to a certain extent, to physically isolate the three lugs10by forming a small partition wall around each lug10to prevent an object or a liquid from falling onto the connection100and thus causing a short-circuit. It is clipped to the vice-type terminal block50. Apart from protecting the connection100, it also serves to prevent the lugs10from exiting the slots61,62. The protective cover70is preferably also made of an insulating material, and can be connected to the vice-type terminal block50as required.

FIG. 5shows a connection200comprising a variant of a vice-type terminal block80similar as a whole to that described hereinabove, however comprising several changes. The fixed plate81is more substantial, having a mounting83in the form of a base plate, and side plates90.

The clamping system comprises four cams86, but in this case, only two cams86are provided with handles allowing for their manual rotation. However, the cams86are all connected in rotation by a bar87, and thus actuation of the two cams86provided with handles actuates all four cams86.

In order to prevent any relative movement between the plates81,82of the terminal block80in the clamped state, the plates81,82comprise cooperating ribs84and grooves85on their sides which face the opposing plate. Moreover, said opposing sides of the plates81,82are provided with counterbores93adapted to receive the flanges12of the lugs10, the counterbores93being circular and provided around the bottom of each slot91,92. This prevents the lugs10from sliding along their slot91,92. The edges of said counterbores93also help support the flanges12such that they are aligned. Finally, two pins89are used (one on the left and one on the right) to properly secure the cams86.

FIG. 6shows the connection200inFIG. 5with a protective cover95positioned on the top of the vice-type terminal block80. The protective cover85comprises a horizontal plate96and side plates97. It further comprises formations for engaging with complementary formations on the fixed plate81of the vice-type terminal block80. In this case, two vertical rods98on the protective cover are slid into the corresponding grooves94on the fixed plate81. Once in place, the protective cover95is secured to the vice-type terminal block80by fixing the pins99onto studs88provided on the fixed plate81.

It will be clear to one skilled in the art that other clamping systems may be suitable instead of the cam-based clamping systems described above for bringing together and clamping the two plates of the vice-type terminal block. For example, a single cam-based system exerting a load over the entire length of the vice-type terminal block can be envisaged. Alternatively, the two plates of the terminal block can be connected by quarter-turn quick connectors, or by another clamping system.

It goes without saying that the vice-type terminal block can receive and connect the lugs of the type described but with the flange connected to the barrel in a non-centred manner, in other words, with its geometric centre not being on the axis. However, lugs having flanges connected in a centred manner are preferred for practical purposes and for a more reliable connection.

Although a terminal block with two plates that move in translation is preferred, the two plates can be designed to pivot relative to one another, for example connected along their lower edge. The terminal block can also be designed to connect more or fewer cables depending on the installation, for example with only two pairs of opposing slots for the two direct voltage cables.

The invention is not limited to the field of aircraft, and is also suitable for use in other fields involving construction in segments or modular construction methods such as those of ships, buildings, or more generally any field in which a cable must be connected to an electrical element.

The embodiment described hereinabove is provided for illustration purposes only and must not be interpreted restrictively. It should be noted that other embodiments or improvements to the invention will be clear to one skilled in the art without departing from the general scope of the claims.