Roller finger follower for valve deactivation
View Patent ↗The finger follower has an inner and outer body and a torsional lost motion spring positioned at its lash adjuster end of the outer body. The torsional lost motion spring has two helical parts each with a short leg that abuts the outer body and a long leg that contacts the inner body. The torsional spring is located above the pivot point of the finger follower so as to provide a low mass moment of inertia and to reduce the weight over the valve stem end of the follower.
1. A switchable roller finger follower comprising:
an outer elongated body having a valve stem end, a lash adjuster end and two outer elongated body side walls;
a first inner cavity in said outer elongated body;
two lost motion spring pins attached to said lash adjuster end of said outer elongated body, said pins oriented transversely to a long axis of said outer elongated body;
a lost motion spring stop located on an outer wall of said elongated body and adjacent said lash adjuster end;
an inner elongated body positioned in said first inner cavity and having a first end pivotally attached to said outer elongated body at said valve stem end a second end adjacent said lash adjuster end of said outer elongated body and two inner elongated body sidewalls;
a second inner cavity in said inner elongated body;
two lost motion spring pallets, one of each of said pallets fixed on one of each of said inner elongated body side walls and adjacent said second end of said inner elongated body;
a center cam follower in said second inner cavity
a latch assembly for preventing pivoting of the inner elongated body; and
a lost motion torsional spring device having two helical parts, one of each of said helical parts on one of each on said lost motion pins, each of said helical parts having a short leg and a long leg, the short leg of each of said helical part abutting said stop and the long leg of each of said helical part abutting one of said pallets.
2. The follower of claim 1 wherein said long leg of each of said helical parts has a contact surface and each of said pallets has a contact surface and said contact surface of said long leg contacts said contact surface of said pallets.
3. The follower of claim 2 wherein said contact surface of each of said pallets is convex.
4. The follower of claim 2 wherein said contact surface of said long leg of each of said helical parts is convex.
5. The follower of claim 2 wherein said contact surface of each of said pallets is convex and said contact surface of said long leg of each of said helical parts is convex.
6. The follower of claim 2 wherein said contact surface of each of said pallets and said contact surface of said long leg of each of said helical parts is involute.
7. The follower of claim 2 wherein said contact surface of said pallet are in rolling contact with said contact surface of said long leg of each of said helical parts is convex.
8. The follower of claim 1 wherein each of said pallets is mounted on an outside surface of said inner elongated body side wall.
9. The follower of claim 1 further comprising a recess in an inside surface of each of said outer elongated body sidewalls for accommodating movement of said pallets.
10. The follower of claim 1 , wherein said short legs are connected to form a bridge and the bridge abuts the stop.
11. The follower of claim 10 , wherein said outer elongated body has an end wall at said lash adjuster end, said end wall is transverse to said outer elongated body side walls, and said stop is on said end wall.
12. The follower of claim 1 , wherein said short legs are separate from each other;
said stop is formed from two steps, one of each of said two stops on said outer elongated body side walls; and
one of each of said short legs abutting one of each of said stops.
13. The follower of claim 2 , wherein the contact surface of the long legs is changed by changing the length of the long leg and the position of the pallet on the side wall of the inner body so as to change the gear ratio.