Granted Patent B2

US 8,845,486 · App. 13/153,147 · Granted Sep 30, 2014

Abstract

Claims (41)

1. Outdoor power equipment, comprising:

an engine comprising a throttle, an engine block, and a drive shaft;

a driven shaft, wherein the driven shaft at least partially extends through the engine block and wherein the drive and driven shafts share a reservoir of lubricant;

a tool coupled to the driven shaft; and

a transmission coupling the drive and driven shafts and providing a mechanical advantage therebetween, wherein the transmission automatically changes the mechanical advantage in response to torque experienced by the driven shaft.

2. The outdoor power equipment of claim 1 , wherein the transmission is a continuously variable transmission.

3. The outdoor power equipment of claim 2 , wherein the transmission comprises:

a first wheel coupled to the drive shaft; and

a second wheel coupled to the driven shaft, wherein a working diameter of the second wheel changes as a function of torque acting on the driven shaft.

4. The outdoor power equipment of claim 3 , wherein the transmission further comprises a belt coupling the first and second wheels, and wherein a working diameter of the first wheel changes as a function of tension in the belt.

5. The outdoor power equipment of claim 2 , further comprising a governor that operates the throttle of the engine as a function of rotational speed of the driven shaft.

6. The outdoor power equipment of claim 5 , wherein the governor is coupled to the driven shaft.

7. The outdoor power equipment of claim 1 , wherein the tool comprises at least one of an auger, a blade, and tines.

8. Outdoor power equipment, comprising:

an engine comprising a throttle and a drive shaft;

a driven shaft;

a tool coupled to the driven shaft;

a continuously variable transmission coupling the drive and driven shafts and providing a mechanical advantage therebetween, wherein the transmission comprises:

a first wheel coupled to the drive shaft;

a second wheel coupled to the driven shaft; and

a belt coupling the first and second wheels;

wherein a working diameter of the second wheel changes as a function of torque acting on the driven shaft, thereby automatically changing the mechanical advantage in response to torque experienced by the driven shaft; and

wherein a working diameter of the first wheel changes as a function of tension in the belt; and

a governor that operates the throttle of the engine as a function of rotational speed of the driven shaft.

9. The outdoor power equipment of claim 8 , wherein the governor is coupled to the driven shaft.

10. The outdoor power equipment of claim 9 , wherein the engine does not include an additional governor.

11. An engine, comprising:

an engine block;

a piston configured to translate in the engine block in response to combustion processes of the engine;

a crankshaft supported by the engine block and coupled to the piston;

an output shaft supported by the engine block and coupled to the crankshaft;

a transmission coupling the crankshaft and the output shaft and providing a mechanical advantage therebetween;

a governor; and

a throttle, wherein the governor operates the throttle of the engine as a function of rotational speed of the output shaft;

wherein the crankshaft and the output shaft share a reservoir of lubricant.

12. The engine of claim 11 , wherein the transmission changes the mechanical advantage in response to torque experienced by the output shaft.

13. The engine of claim 12 , wherein the transmission is a continuously variable transmission and comprises:

a first wheel coupled to the crankshaft;

a second wheel coupled to the output shaft, wherein a working diameter of the second wheel changes as a function of torque in the output shaft; and

a belt coupling the first and second wheels, wherein a working diameter of the first wheel changes a function of tension in the belt.

14. The engine of claim 13 , wherein the second wheel has greater rotational inertia than the first wheel.

Assignments (8)