A folding mechanism comprises a first folding body, a second folding body and a first clamping piece, the second folding body is provided with a second clamping piece, and the first folding body connected to the first clamping piece; and when the first folding body and the second folding body are unfolded, abutting parts of the first clamping piece are clamped in the second clamping piece, and a gap is formed between a non-abutting part of the first clamping piece and the second folding body. The first clamping piece connected to the first folding body is clamped in the second clamping piece on the second folding body to fix the first folding body and the second folding body when the first folding body and the second folding body are unfolded, and the gap is reserved to avoid shakes.

The invention relates to a retaining device for an instrument, comprising at least one joint having at least two parts that can be moved relative to each other and at least one drive unit associated with the joint. The drive unit is designed to move the joint by driving at least one of the parts of the joint that can be moved relative to each other. The retaining device also comprises a securing device, which has a locking mechanism associated with the joint and a release unit that can be activated, wherein the locking mechanism interacts with the release unit in such a way that the locking mechanism holds the joint in a locked position as long as the release unit is not activated. The securing device is designed to permit a motion of the joint out of the particular locked position within a specified range of motion even if the release unit is not activated. The invention further relates to a corresponding securing device for a retaining device and to an operating method for said securing device.

An adjustment coupler includes a first clutch member and a second clutch member. In embodiments, the first clutch member may be rotationally fixed with respect to the second clutch member when a torque applied thereto is less than a predetermined amount. When the torque is greater than or equal to the predetermined amount, the first clutch member may rotate with respect to the second clutch member. In other embodiments, the first clutch member may be rotationally fixed to the second clutch member.

A lockable pivoting articulation joint includes a first joint section, a second joint section, a pivot bearing allowing the first and second joint sections to be rotatable in relation to each other about a main axis, and a locking mechanism on the first joint section switchable between a release condition and a locking condition. The second joint section is lockable in relation to the first joint section in at least one relative rotational position. On the second joint section a retaining surface is provided. The locking mechanism has a clamping lever attached to the first joint section to be pivotable about a clamping lever axis between a locking position and a release position. The clamping lever has a clamping surface for locking abutment on the retaining surface and the clamping surface is inclined in relation to a tangential plane.

Projection and camera systems may employ a joint locking mechanism that may enable a user to reposition or move structures (arms, lenses, etc.) that are otherwise locked in position. The joint locking mechanism may include a touch-activated presence detector to sense a presence of an extremity of a user. In response to the presence detector sensing the presence, an actuator may unlock a joint or structure to enable movement of the joint or structure while the presence detector continues to sense the presence. In response to a detection of an absence of the extremity, the actuator may return to a locked state to prevent further movement of the joint or structure.