The present disclosure describes a wrap spring torque nipple that includes a first helical spring, a second helical spring, and a middle portion connected to and between the first helical spring and the second helical spring. The first helical spring and the second helical spring have different rotational helix orientations, and the first helical spring is configured to receive an input shaft and the second helical spring is configured to receive an output shaft, wherein the wrap spring transfers rotational power up to a defined torsional value from the input shaft to the output shaft.

The present disclosure describes a wrap spring torque nipple that includes a first helical spring, a second helical spring, and a middle portion connected to and between the first helical spring and the second helical spring. The first helical spring and the second helical spring have different rotational helix orientations, and the first helical spring is configured to receive an input shaft and the second helical spring is configured to receive an output shaft, wherein the wrap spring transfers rotational power up to a defined torsional value from the input shaft to the output shaft.

The present disclosure describes a wrap spring torque nipple that includes a first helical spring, a second helical spring, and a middle portion connected to and between the first helical spring and the second helical spring. The first helical spring and the second helical spring have different rotational helix orientations, and the first helical spring is configured to receive an input shaft and the second helical spring is configured to receive an output shaft, wherein the wrap spring transfers rotational power up to a defined torsional value from the input shaft to the output shaft.

The present disclosure describes a wrap spring torque nipple that includes a first helical spring, a second helical spring, and a middle portion connected to and between the first helical spring and the second helical spring. The first helical spring and the second helical spring have different rotational helix orientations, and the first helical spring is configured to receive an input shaft and the second helical spring is configured to receive an output shaft, wherein the wrap spring transfers rotational power up to a defined torsional value from the input shaft to the output shaft.

In an aspect, a method is provided for controlling a clutch assembly having first and second rotatable clutch members. The method includes providing a wrap spring clutch having first and second ends. The phase angle between the first and second ends determines a diameter of the wrap spring clutch. One of the clutch members is connected with the first end. The method further includes obtaining a target value indicative of a target speed for the second clutch member, and determining through measurement an actual value that is indicative of an actual speed of the second clutch member. The method further includes changing the phase angle between the first and second ends of the wrap spring clutch to generate a selected amount of slip between the wrap spring clutch and the other of the first and second clutch members, based on the target value and the actual value.

In an aspect, a method is provided for controlling a clutch assembly having first and second rotatable clutch members. The method includes providing a wrap spring clutch having first and second ends. The phase angle between the first and second ends determines a diameter of the wrap spring clutch. One of the clutch members is connected with the first end. The method further includes obtaining a target value indicative of a target speed for the second clutch member, and determining through measurement an actual value that is indicative of an actual speed of the second clutch member. The method further includes changing the phase angle between the first and second ends of the wrap spring clutch to generate a selected amount of slip between the wrap spring clutch and the other of the first and second clutch members, based on the target value and the actual value.

A knockdown, portable lift is relatively compact and lightweight for transport and use where there is no existing means for lifting a load between a lower surface and an upper surface or where the existing means cannot be used. Components of the lift are stored in a base portion of the lift and are assembled on site for forming a lift frame extending between the upper and lower surfaces. A platform and drive assembly are supported on the lift frame and are driven together up and down tracks on each side of the lift frame using a rotary drive, such as a hand crank or electric motor, to power the drive assembly. The drive assembly is operable by a person on or off the platform from either the upper or lower surface or traversing stairs over which the platform is moving. The drive assembly incorporates a unique overspeed braking system and a unique clutch arrangement.

A knockdown, portable lift is relatively compact and lightweight for transport and use where there is no existing means for lifting a load between a lower surface and an upper surface or where the existing means cannot be used. Components of the lift are stored in a base portion of the lift and are assembled on site for forming a lift frame extending between the upper and lower surfaces. A platform and drive assembly are supported on the lift frame and are driven together up and down tracks on each side of the lift frame using a rotary drive, such as a hand crank or electric motor, to power the drive assembly. The drive assembly is operable by a person on or off the platform from either the upper or lower surface or traversing stairs over which the platform is moving. The drive assembly incorporates a unique overspeed braking system and a unique clutch arrangement.

A clutched driven device (10) having a clutch assembly (16) with a first rotary clutch portion (50), a second rotary clutch portion (52), a bearing (54), a wrap spring (56) and an actuator (60). The first rotary clutch portion has an interior clutch surface (76). The first and second rotary clutch portions are rotatably disposed about a rotary axis (70) of the clutched driven device. The bearing is received between the first and second rotary clutch portions and supports the first rotary clutch portion for rotation on the second rotary clutch portion. The wrap spring is disposed radially inwardly of the bearing and has a plurality of helical coils (114) that are received against the interior clutch surface. The actuator is configured to selectively initiate coiling of the wrap spring to cause the helical coils of the wrap spring to disengage the interior clutch surface to a predetermined extent.

A clutched driven device (10) having a clutch assembly (16) with a first rotary clutch portion (50), a second rotary clutch portion (52), a bearing (54), a wrap spring (56) and an actuator (60). The first rotary clutch portion has an interior clutch surface (76). The first and second rotary clutch portions are rotatably disposed about a rotary axis (70) of the clutched driven device. The bearing is received between the first and second rotary clutch portions and supports the first rotary clutch portion for rotation on the second rotary clutch portion. The wrap spring is disposed radially inwardly of the bearing and has a plurality of helical coils (114) that are received against the interior clutch surface. The actuator is configured to selectively initiate coiling of the wrap spring to cause the helical coils of the wrap spring to disengage the interior clutch surface to a predetermined extent.