Machine element or mechanism – Control lever and linkage systems – Elements
Patent
1996-03-05
1997-12-23
Luong, Vinh T.
Machine element or mechanism
Control lever and linkage systems
Elements
74567, 403320, 403322, G05G 104
Patent
active
056996985
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a system for unfolding or folding up two elements which are linked in terms of rotation, as well as for locking or unlocking of the said elements when they occupy at least the unfolded position.
More specifically, the system is especially applicable to the field of space to allow the unfolding or the folding-up of elements or of structures such as parabolic antennae, active planar antennae, radar antennae, solar panels, deployment masts and the like, relative to space stations or platforms, shuttles, artificial satellites, and also to provide the functions of locking/unlocking the said elements in the unfolded position. Quite clearly the system could find applications in other technical fields, in which the rotation and the locking in a given position of two elements one with respect to the other are to be achieved reliably and robustly.
BACKGROUND OF THE INVENTION
It is known that the unfolding of large elements, such as those listed hereinabove, requires, particularly in the field of space, the production of systems which, in addition to remarkable reliability, guarantee a complete absence of play between the various components forming the system and the elements, and a high degree of rigidity, without fail, when the said elements occupy their unfolded, locked, position. To achieve this, a vigorous locking system meeting these requirements consists in using a cam with a logarithmic profile which is mounted on a rotary shaft linked to one of the elements and which makes it possible to obtain an increasing locking force against a bearing face, provided in a corresponding position on the other element. Nevertheless, the drawback of such a locking system is that it exhibits almost complete irreversibility, which prevents the unfolded element from being folded up, if necessary. Indeed, under the action of vibration, differential expansion due to the effect of temperature gradients, etc., the cam with logarithmic profile tends spontaneously to become engaged to an increasing extent against the bearing face, thus causing increasingly vigorous locking.
Hence, to overcome this drawback and continue to use a cam with a logarithmic profile for the advantages which it affords, the system has been improved particularly by mounting the cam in an offset fashion on the shaft, as taught by French patent 2, 651, 843 or U.S. Pat. No. 5,108,216 of the Applicant Company.
The locking system described therein discloses in particular that: said logarithmic spiral is located, the said shaft being mounted so that it can rotate on the said first element about an axis of rotation which is offset in the opposite direction to the said contact surface of the said cam, with respect to the axis of the said shaft; direction such that the said contact surface moves towards the said bearing face; rotation and which can drive the said cam in rotation in a second direction, opposite to the first, the said stub not preventing the said cam from rotating in the said first direction under the action of the said elastic means; and about the said offset axis of rotation, in the said second direction.
Hence, by offsetting the axes of the cam and of the shaft and through the manual means for rotating the said shaft, it is possible, when the means are actuated following an intervention from outside the vehicle, to get the logarithmic surface of the cam to move away from the said flat bearing face, which in succession allows the second element in the unfolded position to be unlocked from the first element bearing the cam, then to return the second element towards the folded-up position against the first by pivoting about an axis of articulation linking them.
Although this locking system avoids the jamming effect of the cam, it is still no less restrictive in so far as it requires a manual intervention to unlock the cam, then another subsequent intervention to fold up the unfolded element towards the folded-up position.
SUMMARY OF THE INVENTION
The object of the present invention is to over
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Aerospatiale - Societe Nationale Industrielle
Luong Vinh T.
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