Patent ID: 7673840

Claim:
A supporting arm for a projection apparatus, the supporting arm comprising: a first arm section having a longitudinal axes; a second arm section having a longitudinal axes and a free end; the projection apparatus to be fastened on said free end of said second arm section; an articulation apparatus disposed between said first and second arm sections for interconnecting said arm sections, said articulation apparatus being configured to permit said second arm section to rotate through a rotational excursion relative to said first arm section between a first position, in which said longitudinal axes of said arm sections run substantially parallel to one another, and a second position, in which said longitudinal axes of said arm sections run substantially at right angles relative to one another, said articulation apparatus having a guide device guiding a rotational movement of said second arm section relative to said first arm section and delimiting said rotational movement relative to one of said first or second positions of said second arm section relative to said first arm section; and a spring apparatus coupled to said first arm section and to said second arm section and having a spring force selected to compensate for a weight force of said second arm section and of the projection apparatus fastened thereon over substantially all of said rotational excursion of said second arm section relative to said first arm section.