Patent Description:
The use of tubular bodies made of composite material that form part of articulated arms used to deploy space equipment once same is in orbit is known in the state of the art, see e.g. <CIT>.

Said arms are initially folded in the space craft before being launched into space to occupy a reduced space, and once the desired location is reached, they can be deployed through the action of a pyrotechnics mechanism, as happens, for example, in the arms that hold the mirrors of a satellite the equipment then remaining deployed during the orbital displacement cycle.

However, these tubular bodies have various problems due to the material with which they are manufactured. One of them is thermal stability, in the face of extreme temperature conditions existing in space, since they can reach between -<NUM> and +<NUM>. Under these conditions, the composite material may suffer deformations and it may be the case that full unfolding of the arms does not occur, with the problems that this entails.

Moreover, there is also another problem arising from the impossibility of controlling the unfolding, an unfolding being common in this type of elements that ends in a voltage surge, which implies the possibility of structural failures that may affect the operation of the space equipment.

The present invention relates to a fold-out articulated arm, for use in space equipment, which comprises a tubular body made of composite material, such as carbon fibre with epoxy, which integrates at least one strap of metal material practically unalterable under these temperature conditions, which guarantees the unfolding of the articulated arm in space.

The tubular body comprises a first rigid section and a second rigid section, provided with distal ends and facing proximal ends, and a hinged area located between both rigid sections, formed by at least two flexible laminar portions that join the proximal ends of the two rigid sections, allowing the folding and unfolding of the first rigid section with respect to the second.

In accordance with the present invention, the articulated arm additionally comprises reinforcements, associated with each of the rigid sections, and, at least, the aforementioned metal strap, which is flexible, is joined at its ends to one of the reinforcements and passes through a slot that the other reinforcement incorporates to facilitate the extension or retraction of the strap during its folding or unfolding.

The metal strap facilitates the folding and unfolding of the first rigid section with respect to the second by transmitting bending stresses to said sections, under extreme temperature conditions, overcoming the defects associated with the possible structural degradation of the material of the tubular body.

In this way, with a metallic material that is practically unalterable at these extreme temperatures and sudden changes in temperature, it is guaranteed that the articulated arm will unfold.

Optionally, the possibility is contemplated that the arm incorporates two parallel straps, located between the reinforcements, as well as that one of the straps is made of a metal material and the other strap is made of a material different from the previous one.

The rigid sections preferably have a circular tubular cross section, the reinforcements can be located at the proximal ends of the rigid sections and said reinforcements can be bushings fitted inside the rigid sections, with a diametrical geometry, the external diameter of which is complementary to the internal diameter of each rigid section of the tubular body, as well as the reinforcements can incorporate a central opening to facilitate the passage of cables or others.

The articulated arm object of the invention may additionally comprise a tie rod, such as a cable, a chain, a rope, etc.; and at least one traction mechanism associated with that tie rod that is conveniently linked to at least the first rigid section to facilitate its controlled unfolding/folding with regard to the second rigid section.

The traction mechanism comprises a pulley, for example, on which the tie rod is wound, the movement of which is controlled by an eddy current type motor or by a viscous brake, for example which initially keeps the tie rod tensioned in the folded situation of the tubular body. In this folded position, the rigid sections can be linked by a joining element associated with a pyrotechnic device, position in which the equipment to be released into space is normally transported.

Once in space, when the articulated arm is to be unfolded, the pyrotechnic device is actuated which releases the first rigid section with respect to the second, and the traction mechanism progressively releases the tie rod in a controlled manner until the tubular body is unfolded.

Optionally, and in order to facilitate the unfolding of the articulated arm in space, the possibility is contemplated that one of the laminar portions is made of a flexible resin and the other laminar portion is made of a rigid resin.

Preferably, the tie rod is linked to the first rigid section at its distal end and it protracts until it is linked to one of the laminar portions. In this situation, when the first section is initially folded, the traction mechanism is tensioning the tie rod. From this position, when the arm is to be unfolded, the traction mechanism gradually releases the tie rod so that the first rigid section progressively tilts around the hinged area until it is in a collinear position with the second rigid section, thus achieving the total unfolding of the tubular body in a controlled manner.

In another embodiment, two tie rods and two traction mechanisms can be used, wherein one of the tie rods is joined to the first rigid section and the other tie rod is joined to one of the laminar portions, so that, as the straps are released from each of the traction mechanisms, the tilting movement of the first rigid section with respect to the second will be facilitated, and, consequently, the controlled and coordinated unfolding of the tubular body.

As a complement to the description provided herein, and for the purpose of helping to make the features of the invention more readily understandable, in accordance with a preferred practical exemplary embodiment thereof, said description is accompanied by a set of drawings constituting an integral part of the same, which by way of illustration and not limitation, the following has been represented:.

With the aid of the figures, a preferred embodiment of the fold-out articulated arm object of this invention is described below.

<FIG> shows an upper perspective view of the fold-out articulated arm, formed by a tubular body (<NUM>) made of composite material, preferably carbon fibre with epoxy, which is equipped with a first rigid section (<NUM>) and a second rigid section (<NUM>) that are equipped with distal ends, and facing proximal ends, and a hinged area (<NUM>) located between both rigid sections (<NUM>, <NUM>) which is formed by at least two flexible laminar portions (<NUM>) that join the proximal ends of both rigid sections (<NUM>, <NUM>).

<FIG> shows reinforcements (<NUM>) that are linked to each of the rigid sections (<NUM>, <NUM>), as seen in <FIG>, and a flexible metal strap (<NUM>) linked by its ends to both reinforcements (<NUM>), which, as can be seen in <FIG>, protracts close to one of the laminar portions (<NUM>).

<FIG> show the metal strap (<NUM>) in a straight position, corresponding to the unfolded situation of the articulated arm. <FIG> shows that the metal strap (<NUM>) is initially bent and tensioned, and that in <FIG>, once this folding situation is released, it favours the unfolding of the first rigid section (<NUM>) with respect to the second rigid section (<NUM>) around the hinged area (<NUM>) to recover its straight position, this movement being reproduced for whatever temperature in the environment in which the articulated arm is located, due to the metallic nature of the metal strap (<NUM>).

In <FIG>, it can be seen that the reinforcements (<NUM>) are located at the proximal ends of the rigid sections (<NUM>, <NUM>), said reinforcements (<NUM>) able to be bushings (<NUM>), as can be seen in <FIG>, coupled inside the rigid sections (<NUM>, <NUM>), wherein each bushing (<NUM>) has a central opening (<NUM>) that allows the passage of cables and other elements.

The strap (<NUM>) is fixed to one of the bushings (<NUM>) and the other bushing (<NUM>) has a through slot (<NUM>) that facilitates the extension or retraction movement of the strap (<NUM>) during its folding or unfolding.

Moreover, it should be noted that in order to facilitate the unfolding of the articulated arm, same has at least one tie rod (<NUM>), as can be seen in <FIG>, and that the rigid sections (<NUM>, <NUM>) have first facing holes (<NUM>) at their distal ends, as well as the laminar portions (<NUM>) have second centred holes (<NUM>) and the strap (<NUM>) has a third central hole (<NUM>), said holes (<NUM>, <NUM>, <NUM>) being intended to facilitate the passage or tying of the tie rod (<NUM>).

<FIG> show the unfolding process of a first embodiment of the articulated arm, which comprises a tie rod (<NUM>) and a traction mechanism that actuates a first pulley (<NUM>) in which this tie rod (<NUM>) is wound, wherein the tie rod (<NUM>), as can be seen in <FIG>, goes through a first hole (<NUM>) of the first rigid section (<NUM>), as well as then goes through the first two holes (<NUM>) of the second rigid section (<NUM>) and protracts through the second hole (<NUM>) of one of the laminar portions (<NUM>), to then pass through the central hole (<NUM>) of the strap (<NUM>) until being tied in the other second hole (<NUM>) of the other laminar portion (<NUM>), such that, as can be seen in <FIG>, as the first pulley (<NUM>) progressively releases the tie rod (<NUM>), the controlled unfolding of the first rigid section (<NUM>) with respect to the second rigid section (<NUM>) is caused until reaching the unfolded position of <FIG>.

In the case of <FIG>, a second embodiment of the articulated arm is observed in which the tie rod (<NUM>), as seen in <FIG>, goes through the first two holes (<NUM>) of the second rigid section (<NUM>) and it protracts through the second hole (<NUM>) of one of the laminar portions (<NUM>), to then go through the central hole (<NUM>) of the strap (<NUM>) until being tied in the other second hole (<NUM>) of the other laminar portion (<NUM>), such that, as can be seen in <FIG>, as the first pulley (<NUM>) progressively releases the tie rod (<NUM>), the controlled unfolding of the first rigid section (<NUM>) with respect to the second rigid section (<NUM>) is caused until reaching the unfolded position of <FIG>.

In the case of <FIG>, a third embodiment of the articulated arm is observed in which the tie rod (<NUM>), as seen in <FIG>, is tied to a first hole (<NUM>) of the second rigid section (<NUM>), and includes a second pulley (<NUM>) with another tie rod (<NUM>) that goes through a second hole (<NUM>) of one of the laminar portions (<NUM>), to then go through the central hole (<NUM>) of the strap (<NUM>) until it is tied in the other second hole (<NUM>) of the other laminar portion (<NUM>), such that, as can be seen in <FIG>, as the pulleys (<NUM>, <NUM>) progressively release their respective tie rod (<NUM>), the controlled unfolding of the first rigid section (<NUM>) with respect to the second rigid section (<NUM>) is caused until reaching the unfolded position of <FIG>.

In the case of <FIG>, a fourth embodiment of the articulated arm is observed in which the tie rod (<NUM>), as seen in <FIG>, is tied to a first hole (<NUM>) of the second rigid section (<NUM>), and includes a second pulley (<NUM>) with another tie rod (<NUM>) that is inserted interiorly through the first rigid section (<NUM>), goes through the central opening (<NUM>) of the reinforcement (<NUM>) and is tied in the second hole (<NUM>) of the upper laminar portion (<NUM>), such that, as can be seen in <FIG>, as the pulleys (<NUM>, <NUM>) progressively release their respective tie rod (<NUM>), the controlled unfolding of the first rigid section (<NUM>) with respect to the second rigid section (<NUM>) is caused until reaching the unfolded position of <FIG>.

Claim 1:
A fold-out articulated arm, for use in space equipment, comprising a tubular body (<NUM>) made of composite material comprising:
- a first rigid section (<NUM>) and a second rigid section (<NUM>) provided with distal ends and with facing proximal ends, and
- a hinged area (<NUM>) located between both rigid sections (<NUM>, <NUM>) which is formed by at least two flexible laminar portions (<NUM>) that join the proximal ends of both rigid sections (<NUM>, <NUM>),
characterised in that the fold-out articulated arm additionally comprises:
- respective reinforcements (<NUM>), each of them coupled inside one of the rigid sections (<NUM>, <NUM>), and
- at least one flexible metal strap (<NUM>) equipped with ends, wherein each end is linked to one of said reinforcements (<NUM>), which favours the unfolding of the first rigid section (<NUM>) with respect to the second rigid section (<NUM>) around the hinged area (<NUM>) under extreme temperature conditions.