One aspect is a wrap spring clutch with a rotatable input and a spring having a first and a second end and having an equilibrium state and a flexed state, the spring engaged with the input through one of the first and second ends such that the spring rotates with the input and with an input torque transmitted exclusively through one of the first and second ends when the input rotates. A damper mechanism is engaged with one of the first and second ends such that the damper mechanism causes the spring to change from its equilibrium to its flexed state when the input transitions from stationary to rotational, and such that the damper mechanism allows the spring to change from its flexed to its equilibrium state when the input transitions from rotational to stationary. A rotatable output is positioned relative to the spring such that the output synchronously rotates with the input when the spring is in its flexed state and rotates independently of the input when the spring is in its equilibrium state.

A method for installing a wrap spring includes providing a first sleeve with a first longitudinal axis extending in an axial direction and a lateral surface, and the wrap spring designed to frictionally abut the lateral surface. The wrap spring includes a nominal diameter and a central axis. The method includes applying the wrap spring in a relaxed state to the lateral surface at an angle α between the central axis and the first longitudinal axis, elastically twisting the wrap spring to change the nominal diameter while the wrap spring contacts the lateral surface, reducing the angle α, threading the wrap spring onto the first sleeve, and relaxing the wrap spring to establish frictional contact with the lateral surface.

A method for installing a wrap spring includes providing a first sleeve with a first longitudinal axis extending in an axial direction and a lateral surface, and the wrap spring designed to frictionally abut the lateral surface. The wrap spring includes a nominal diameter and a central axis. The method includes applying the wrap spring in a relaxed state to the lateral surface at an angle α between the central axis and the first longitudinal axis, elastically twisting the wrap spring to change the nominal diameter while the wrap spring contacts the lateral surface, reducing the angle α, threading the wrap spring onto the first sleeve, and relaxing the wrap spring to establish frictional contact with the lateral surface.

A rotary clutch uses a wrap spring clutch. An actuator generates a drag force to control the wrap spring clutch to engage or disengage the clutch. The actuator includes an electromagnet, a two-component armature and an axial return spring. The two-component armature includes first and second components threadingly connected one another for relative axial translation as they rotate relative to one another, and an angular position biasing member connecting them. The second component translates axially under magnetic force from the electromagnet, and when stopped by the electromagnet the first armature component translates axially due to their threaded connection. Due to the previous axial movement of the floating component the translation of the first armature component occurs in conditions where the air gap and reluctance of a magnetic circuit is reduced compared to the prior art, and thus the overall strength of the applied magnetic field can be comparatively reduced.

A rotary clutch uses a wrap spring clutch. An actuator generates a drag force to control the wrap spring clutch to engage or disengage the clutch. The actuator includes an electromagnet, a two-component armature and an axial return spring. The two-component armature includes first and second components threadingly connected one another for relative axial translation as they rotate relative to one another, and an angular position biasing member connecting them. The second component translates axially under magnetic force from the electromagnet, and when stopped by the electromagnet the first armature component translates axially due to their threaded connection. Due to the previous axial movement of the floating component the translation of the first armature component occurs in conditions where the air gap and reluctance of a magnetic circuit is reduced compared to the prior art, and thus the overall strength of the applied magnetic field can be comparatively reduced.

A variety of brake and/or clutch mechanisms, and improvements thereof, are provided having improved braking power, reduced size and weight, and other benefits. The braking mechanisms include a wrap spring clutch that is operable to mechanically couple a rotating member to a brake rotor that is in consistent contact with a brake pad. Actuation of the wrap spring clutch allows the wrap spring to engage with the rotating member, coupling the rotating member to the brake rotor thus braking the rotating member. The combination of the wrap spring clutch with the brake rotor and pad provides an overall braking mechanism that exhibits the decreased power cost, weight, size, and engagement time of the wrap spring clutch while having a braking power that can be moderated by specifying the area, engagement force, coefficient of friction, or other properties of the brake rotor and pad.

A shifting system includes an input member, a disconnect, an output member, and a shifting assembly to selectively rotationally couple the input member and the output member. The shifting assembly includes an input hub having a disconnectable component engageable with the disconnect and a clutch engagement component extending radially away from an axis. A plurality of clutch plates is coupled to the clutch engagement component and is moveable between engaged and disengaged positions. A biasing member is coupled to the clutch plates to bias the clutch plates toward the engaged position, and an apply plate is coupled to the biasing member. The apply plate is moveable between a first plate position where the clutch plates are in the engaged position, and a second plate position where the clutch plates are in the disengaged position. A clutch plate carrier is coupled to the clutch plates and to the output member.

The present invention relates to a pulley structure (1) equipped with an outer rotating body (2), an inner rotating body (3), and a coil spring (4) provided between the outer rotating body (2) and the inner rotating body (3). The coil spring (4) is configured so as to undergo torsional deformation in a diameter-expanding or a diameter-contracting direction, thereby engaging the outer rotating body (2) and the inner rotating body (3) and transmitting torque, and to undergo torsional deformation in the direction opposite the direction in which torque is transmitted, thereby entering a disengaged state in which the coil spring slides with the outer rotating body (2) or the inner rotating body (3), thus interrupting the transmission of torque. The number of windings of the coil spring (4) is in a range between [M-0.125] and M (both inclusive), where M is a natural number.

A gear apparatus for controlling movement of an output by an input coupled to a power source. The apparatus an input member coupled to the input, an output member coupled to the output and the input member so that movement of the input member causes movement of the output, a selectably releasable member coupled to the input member and the output member, wherein the selectably releasable member remains in a fixed position while the input member and the output member move, and a releasable member brake mechanism coupled to the selectably releasable member, wherein the releasable member brake mechanism is arranged to prevent movement of the selectably releasable member when the input member and the output member move and to allow back driving of the selectably releasable member.

A gear apparatus for controlling movement of an output by an input coupled to a power source. The apparatus an input member coupled to the input, an output member coupled to the output and the input member so that movement of the input member causes movement of the output, a selectably releasable member coupled to the input member and the output member, wherein the selectably releasable member remains in a fixed position while the input member and the output member move, and a releasable member brake mechanism coupled to the selectably releasable member, wherein the releasable member brake mechanism is arranged to prevent movement of the selectably releasable member when the input member and the output member move and to allow back driving of the selectably releasable member.