Self-engaging clutch
A clutch assembly for selectively rotationally coupling a prime mover to an output comprises an input member including an input clutch protrusion, an output member including an output clutch protrusion, and an intermediate member positioned between the input member and the output member. The intermediate member includes a first clutch member engaged with the input clutch protrusion and a second clutch member axially spaced from, but engagable with, the output clutch protrusion. The intermediate member is axially displaceable toward the output member to engage the second clutch member with the output clutch protrusion in response to rotation of the input member relative to the intermediate member.
1. A clutch assembly for selectively rotationally coupling a prime mover to an output, the clutch assembly comprising:
an input member including an input clutch protrusion;
an output member including an output clutch protrusion;
an intermediate member positioned between the input member and the output member, the intermediate member including a first clutch member engaged with the input clutch protrusion and a second clutch member axially spaced from, but engagable with, the output clutch protrusion; and
a friction ring disposed concentrically about the intermediate member and engaging the intermediate member to resist rotation of the intermediate member relative to the output member;
wherein the intermediate member is axially displaceable toward the output member to engage the second clutch member with the output clutch protrusion in response to rotation of the input member relative to the intermediate member; and
wherein, subsequent to engagement of the second clutch member and the output clutch protrusion, the friction ring allows the intermediate member to rotate with the input member and the output member.
2. The clutch assembly of claim 1 , wherein the input clutch protrusion includes a ramped surface and an end wall.
3. The clutch assembly of claim 2 , wherein the first clutch member includes a flat face engagable with the end wall.
4. The clutch assembly of claim 3 , wherein rotation of the input member causes the first clutch member to cam along the ramped surface to axially displace the intermediate member until the flat face engages the end wall.
5. The clutch assembly of claim 1 , wherein the intermediate member is in a disengaged configuration when the input member is stationary, and the intermediate member is in an engaged configuration after the input member begins to rotate.
6. The clutch assembly of claim 1 , wherein the input member includes a first clutching arrangement, of which the input clutch protrusion is a portion, that faces the first clutch member, and wherein the output member includes a second clutching arrangement, of which the output clutch protrusion is a portion, that faces the second clutch member.
7. The clutch assembly of claim 6 , further comprising a biasing member biasing the intermediate member axially away from the output member and toward a first position in which the second clutching arrangement and the second clutch member are adjacent one another.
8. The clutch assembly of claim 7 wherein rotation of the input member relative to the intermediate member in a first direction moves the intermediate member toward a second position in which the second clutching arrangement and the second clutch member are engaged to produce co-rotation of the input member and the intermediate member.
9. The clutch assembly of claim 8 , wherein the intermediate member is moved from the first position to the second position when the input member is driven to rotate such that no direct operation of the clutch assembly by a user is required.
10. The clutch assembly of claim 8 , wherein the first clutching arrangement and the first clutch member are engaged to produce co-rotation of the intermediate member and the input member.
11. The clutch assembly of claim 8 , wherein the second clutching arrangement includes a first ramped cam surface and a first flat face.
12. The clutch assembly of claim 11 , wherein the second clutch member includes a first ramped cam surface and a second flat face.
13. The clutch assembly of claim 12 , wherein the first flat face and the second flat face are engaged in the second position of the intermediate member such that the intermediate member transmits torque to the output member to co-rotate the input member and the output member.
14. The clutch assembly of claim 1 , wherein the clutch assembly is disposed within a lawn mower.
15. A method of operating a clutch assembly including an input member, an output member, and an intermediate member engaged with the input member and engageable with the output member, the method comprising:
spacing the intermediate member away from the output member when the input member is at rest;
resisting rotation of the intermediate member relative to the output member with a friction ring disposed concentrically about the intermediate member;
rotating the input member relative to the intermediate member to induce axial displacement of the intermediate member toward the output member, thereby engaging the intermediate member and the output member; and
subsequent to engagement of the intermediate member and the output member, allowing the the input member, the intermediate member, and the output member to co-rotate relative to the friction ring.
16. The method according to claim 15 , wherein the input member includes a ramped clutch interface that engages a first side of the intermediate member.
17. The method according to claim 16 , wherein rotating the input member causes the first side to slide along the ramped clutch interface, causing axial displacement of the intermediate member relative to the input member.
18. The method according to claim 15 , wherein engaging the intermediate member with the output member requires no direct operation of the clutch assembly by a user.