A rotary actuator has a rotatable platform rotatably supported on a base. The rotatable platform has a friction surface. An actuator band is operated by a band clamp so as to be selectively frictionally engageable with the friction surface. A motion actuator is coupled between the base and the actuator band such that change in length of the motion actuator causes corresponding movement of the actuator band. A brake band is operated by a brake band actuator so as to be selectively frictionally engageable with the friction surface, the brake band anchored to the base.

The disclosure relates to a frictionally locking arrangement for a drive, which drive has an advancing gear mechanism, the frictionally locking arrangement having a carrier and at least one frictionally locking unit. In some embodiments at least one frictionally locking unit has a frictionally locking lever which is mounted with a first lever end pivotably on the carrier, which frictionally locking lever, on a first lever section which is spaced apart from the first lever end, has a force introduction device which is mounted on the carrier and is configured to introduce a force into the frictionally locking lever in a manner which is spaced apart from the first lever end, and which frictionally locking lever, on a second lever section which is arranged between the first lever end and the first lever section, has a first frictional element.

A column-type combination climbing exercise machine mainly includes: the bottom end of a stand frame provided with a ground seat; a column is locked with the stand frame through a locking component; two sliding chutes are respectively disposed at the opposite left and right sides of the column; two sliding seats are correspondingly disposed in the two sliding chute, each sliding seat is adjacent to the top thereof, and a handle and a pedal are respectively disposed at the two ends of the bottom; a first linkage mechanism is connected with the two sliding seats to form a mutually opposite lift-fall and linkage action; a damper is assembled in the ground seat; two connectors are respectively disposed in the two sliding a seat; and a second linkage mechanism makes the damper and the two sliding seats in a linkage relationship.

A small and compact rotation transmitter includes a torque limiter and an angular position holding apparatus. An outer race member is installed in a housing, and a coil spring is mounted on the outer peripheral surface thereof. Inside the outer race member, an internal space is formed, and an inner race member is installed concentrically with the outer race member. In the annular space between the outer and inner race members, a thin-plate elastic piece is pressed against the outer and inner race members, and either the outer or inner race member is connected to an input-side device while the other is connected to an output-side device. Even without rotation torque, the position of the output-side device is held by the coil spring. When the rotation torque from the input-side device becomes excessive, slippage occurs on the thin-plate elastic piece, whereby the outer and inner race members are disconnected.

A small and compact rotation transmitter includes a torque limiter and an angular position holding apparatus. An outer race member is installed in a housing, and a coil spring is mounted on the outer peripheral surface thereof. Inside the outer race member, an internal space is formed, and an inner race member is installed concentrically with the outer race member. In the annular space between the outer and inner race members, a thin-plate elastic piece is pressed against the outer and inner race members, and either the outer or inner race member is connected to an input-side device while the other is connected to an output-side device. Even without rotation torque, the position of the output-side device is held by the coil spring. When the rotation torque from the input-side device becomes excessive, slippage occurs on the thin-plate elastic piece, whereby the outer and inner race members are disconnected.

A brake apparatus for restricting rotation of a rotatable member of a mowing machine, thereby controlling rotation of a wheel of the mowing machine, includes a brake member fixable on the rotatable member, and a gripping member for engaging and disengaging the brake member for restricting or permitting rotation of the rotatable member. A thrust link is coupled to the gripping member such that movement of the thrust link causes the gripping member to engage or disengage a radially outer surface of the brake member. For example, the gripping member may be biasedly engaged with at least a partial circumferential extent of the brake member such that actuation of the thrust link causes disengagement of the gripping member from the brake member.

A brake apparatus for restricting rotation of a rotatable member of a mowing machine, thereby controlling rotation of a wheel of the mowing machine, includes a brake member fixable on the rotatable member, and a gripping member for engaging and disengaging the brake member for restricting or permitting rotation of the rotatable member. A thrust link is coupled to the gripping member such that movement of the thrust link causes the gripping member to engage or disengage a radially outer surface of the brake member. For example, the gripping member may be biasedly engaged with at least a partial circumferential extent of the brake member such that actuation of the thrust link causes disengagement of the gripping member from the brake member.

A positive positioning device comprises a plurality of stacked plates, a body, a spring-biased piston and a piston release device. The plurality of stacked plates have a central opening defined to receive a pivot shaft. The body houses the plurality of stacked plates and has an internal bore within which a cylinder is defined. The spring-biased piston is shaped to slide within the bore to apply a force to the stacked plates to resist rotation of a pivot shaft inserted through the central opening in the stacked plates. The piston release device is actuatable by a user to release the piston to decrease force applied to the stacked plates and allow free rotation of the pivot shaft.

The invention relates to a safety brake system comprising a round rotatable shaft locked with a constant-on braking device activated by a spring and a switch-off device for the braking device that counteracts the spring, so that the shaft is unlocked and can rotate when the switch-off device is active. According to the invention the constant-on brake device comprises a brake shoe pushed against the shaft by the spring and the switch-off device is a piezo actuator that counteracts the spring. The brake system is normally constant on since the spring pushes the brake shoe against the shaft. When the shaft needs to rotate the piezo actuator counteracts the spring, thus releasing the brake shoe from the shaft. In case of an emergency or when the shaft needs to be locked, the power to the piezo activator is shut off and the spring pushes the brake shoe against the shaft to stop any rotation.

The invention relates to a safety brake system comprising a round rotatable shaft locked with a constant-on braking device activated by a spring and a switch-off device for the braking device that counteracts the spring, so that the shaft is unlocked and can rotate when the switch-off device is active. According to the invention the constant-on brake device comprises a brake shoe pushed against the shaft by the spring and the switch-off device is a piezo actuator that counteracts the spring. The brake system is normally constant on since the spring pushes the brake shoe against the shaft. When the shaft needs to rotate the piezo actuator counteracts the spring, thus releasing the brake shoe from the shaft. In case of an emergency or when the shaft needs to be locked, the power to the piezo activator is shut off and the spring pushes the brake shoe against the shaft to stop any rotation.