Brake assembly for dental tray support arm

A support arm for supporting an object at a multitude of positions comprising:

• a first elongate member;
• a second elongate member;
• means for connecting said first and second elongate members adjacent each end thereof in a substantially parallel configuration;
• and
• a brake assembly comprising:
• means releasably engaging a portion of said first elongate member, said engaging means comprising a first brake shoe adapted to engage a first portion of the first of said elongate members;
• means connecting said engaging means to the second of said elongate members, said connecting means being adapted for slidably connecting said first brake shoe with the second of said elongate members;
• and
• fluid operated means actuating said engaging means, whereby relative movement of the first and second elongate members is prevented when said actuating means causes said engaging means to engage said portion of said first elongate member.

A support arm for supporting an object at a multitude of positions comprising:

• an elongate member having two opposed, generally planar vertical sides and a generally planar crosspiece extending between said vertical sides, defining an upper channel and a lower channel;
• a pair of parallel arms extending substantially the length of said crosspiece within said upper channel;
• a pair of first and second rigid members pivotably connected between said pair of parallel arms and said crosspiece adjacent the ends thereof and maintaining said pair of parallel arms and said elongate member in a substantially parallel configuration;
• and
• a brake assembly comprising a first brake shoe slidably connected to said pair of parallel arms, and fluid actuated means for releasably moving said first brake shoe into engagement with a portion of said crosspiece, whereby movement of said parallel arms and said crosspiece relative to each other is prevented when said first brake shoe is engaged with the portion of said crosspiece.