A medical device assembly including a support member, a first arm rotatably connected to the support member at a first rotary axis, a second arm rotatably connected to the first arm at a second rotary axis, and a medical unit connected to an end of the second arm opposite the first arm. The first arm is prevented from rotating about the first rotary axis when the first arm and the second arm are substantially aligned. The first arm and/or the second arm can also be prevented from rotating to prevent the medical device assembly from abutting against an obstacle.

A position-measuring device includes a graduation carrier which carries a measuring graduation and is non-rotatably connectable to a shaft. A scanner is configured to generate scanning signals by scanning the measuring graduation. Evaluation electronics are configured to process the scanning signals into a digital angle value of the shaft. An interface is configured to communicate with subsequent electronics. The scanner is mountable on a machine part that is supported so as to be movable in an axial direction of the shaft, so that the scanning signals are dependent on a position of the machine part in the axial direction of the shaft, and so that a measure of the position of the machine part in the axial direction of the shaft is determinable from the scanning signals by the evaluation electronics.

The application provides a rotating device, including: an annular base, a first positioning member, a second positioning member, and a driving member. The driving member includes a pushing structure. The driving member drives the pushing structure to rotate around the outer edge of the peripheral portion in a first rotating direction or a second rotating direction; when the pushing structure rotates in the first rotating direction, the first stop portion and the third stop portion fit the peripheral portion in response to the push of the pushing structure, and the second stop portion and the fourth stop portion stop the pushing structure; and when the pushing structure rotates in the second rotating direction, the second stop portion and the fourth stop portion fit the peripheral portion in response to the push of the pushing structure, and the first stop portion and the third stop portion stop the pushing structure.

The application provides a rotating device, including: an annular base, a first positioning member, a second positioning member, and a driving member. The driving member includes a pushing structure. The driving member drives the pushing structure to rotate around the outer edge of the peripheral portion in a first rotating direction or a second rotating direction; when the pushing structure rotates in the first rotating direction, the first stop portion and the third stop portion fit the peripheral portion in response to the push of the pushing structure, and the second stop portion and the fourth stop portion stop the pushing structure; and when the pushing structure rotates in the second rotating direction, the second stop portion and the fourth stop portion fit the peripheral portion in response to the push of the pushing structure, and the first stop portion and the third stop portion stop the pushing structure.

An apparatus (B) controls rotation of an annular member (36) relative to top and bottom housings (12, 10). The bottom housing (10) includes a disk (110) extending radially and terminating in a cylindrical portion (112) having circumferentially spaced slits (212). A wedge (16) abuts with the cylindrical portion (112) and is moved radially between first and second positions by an axially moveable piston (14), with the wedge including an angle surface (340) which interfaces with an angled surface (520) of the piston (14) through a plurality of balls (18). The disk (110) and the cylindrical portion (112) are formed as a single component of material having sufficient material strength and yield to allow engagement and disengagement of the cylindrical portion (112) with the annular member (36). The wedge (16) is slideable between an axial surface (250) of the disk (110) and a guiding flange (450) of the top housing (16).

An apparatus (B) controls rotation of an annular member (36) relative to top and bottom housings (12, 10). The bottom housing (10) includes a disk (110) extending radially and terminating in a cylindrical portion (112) having circumferentially spaced slits (212). A wedge (16) abuts with the cylindrical portion (112) and is moved radially between first and second positions by an axially moveable piston (14), with the wedge including an angle surface (340) which interfaces with an angled surface (520) of the piston (14) through a plurality of balls (18). The disk (110) and the cylindrical portion (112) are formed as a single component of material having sufficient material strength and yield to allow engagement and disengagement of the cylindrical portion (112) with the annular member (36). The wedge (16) is slideable between an axial surface (250) of the disk (110) and a guiding flange (450) of the top housing (16).

A rotary device includes a rotatable member and a limiting member. The rotatable member includes a positioning mechanism, the positioning mechanism includes a stopping member and a positioning member. When the rotatable member rotates along a first rotation direction to make the limiting member abut against the positioning member, the positioning member is pushed by the limiting member to move away from the stopping portion and rotate relative to the stopping member, so that the positioning member to passes through the limiting member; when the rotatable member rotates along a second rotation direction opposite to the first rotation direction to make the limiting member abut against the positioning member, the positioning member is pushed by the limiting member to move close to the stopping portion, so that the positioning member is stopped between the limiting member and the stopping portion, to position the rotatable member.

In one embodiment, a ball joint comprises a base that includes a first surface that defines a hemispherical chamber and an electromagnet located internal to the base. The ball joint further comprises an armature plate fastened to the first surface of the housing and defining an aperture that extends through the armature plate towards the hemispherical chamber. The ball joint further comprises a shaft that extends through the aperture of the armature plate and has a rounded end that engages the hemispherical chamber of the housing. Powering the electromagnet draws the armature plate towards the first surface to provide compressive force to the shaft and prevents movement of the shaft.

A door component has a controllable damper device that contains a magnetorheological fluid as a working fluid. Two connection units of the damper device can be moved relative to each other. One of the two connection units can be connected to a support structure, and the other connection unit can be connected to a pivotal door device in order to damp a movement of the door device between a closed position and an open position in a controlled manner. The magnetorheological damper device has a piston unit and a cylinder unit which surrounds the piston unit. The piston unit divides a cylinder volume into two chambers. The piston unit has a first piston rod, which extends through the first chamber, and a second piston rod, which extends through the second chamber.

A door component has a controllable damper device that contains a magnetorheological fluid as a working fluid. Two connection units of the damper device can be moved relative to each other. One of the two connection units can be connected to a support structure, and the other connection unit can be connected to a pivotal door device in order to damp a movement of the door device between a closed position and an open position in a controlled manner. The magnetorheological damper device has a piston unit and a cylinder unit which surrounds the piston unit. The piston unit divides a cylinder volume into two chambers. The piston unit has a first piston rod, which extends through the first chamber, and a second piston rod, which extends through the second chamber.