Internal-combustion engines – Starting device – Mechanical
Reexamination Certificate
2000-08-23
2001-12-04
Dolinar, Andrew M. (Department: 3747)
Internal-combustion engines
Starting device
Mechanical
C123S185800, C185S0410WW, C074S00700R
Reexamination Certificate
active
06325036
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to starting and stopping devices for internal combustion engines.
BACKGROUND
It is known to provide an engine starting device that utilizes stored energy in a spring to rotate the crankshaft and to start the engine. In these engine starting devices, a mechanism must be provided to wind the spring. For example, U.S. Pat. No. 1,936,554, which is assigned to Briggs and Stratton Corporation (the assignee of the present invention) discloses an electric motor that is positioned adjacent the spring and which may be operated to wind the spring. It is also known to provide a manual crank mechanism interconnected with the spring and operable to wind the spring. Further, it is known to provide a winding mechanism interconnected with the crankshaft that is operable to wind the spring during normal engine running conditions.
SUMMARY
The present invention provides an internal combustion engine having a rotatable engine member, a shaft rotatable in a loading direction in response to rotation of said rotatable engine member, and an energy storing mechanism including at least one elastic member that is selectively coupled to the shaft and loaded by rotation of the shaft in the loading direction. Preferably, the engine further includes a locking mechanism selectively maintaining the elastic member in a loaded state, and a clutch mechanism permitting rotation of the shaft in an unloading direction when a preselected torsional threshold between the shaft and the locking mechanism is reached.
Preferably, the locking mechanism includes a ratchet member, and the clutch mechanism couples the ratchet member to the shaft by friction. The locking mechanism may further include a pawl and a pawl carrier. The pawl selectively prevents rotation of the ratchet member in the unloading direction, and the pawl carrier selectively moves the pawl into and out of engagement with the ratchet member. The engagement between the pawl and the ratchet member creates a line of force that self-energizes the pawl into engagement with the ratchet member when the pawl engages the ratchet member. The pawl carrier is positioned such that the line of force urges the pawl carrier to disengage the pawl from the ratchet member when the pawl engages the ratchet member. A shaft is selectively positioned in a slot in the pawl carrier to substantially prevent undesired disengagement of the pawl from the ratchet member. The pawl carrier is permitted to disengage the pawl from the ratchet member when the shaft is removed from the slot in the pawl carrier.
The engine may further include a gear having a central recessed portion that houses the clutch mechanism. The clutch mechanism may include a clutch plate, clutch washer, and spring washer. A clutch cover is preferably positioned over the recessed portion of the gear to pre-load the clutch mechanism. A brake disk is preferably positioned within the recessed portion of the gear, and the clutch mechanism is preferably sandwiched between the brake disk and the clutch cover to create friction between the brake disk and the gear and between the brake disk and the clutch plate. The ratchet member preferably includes depending ears that engage the clutch plate and couple the ratchet member and clutch plate for rotation together.
A pawl control member may be used to disengage the pawl from the ratchet member during loading of the elastic member. The pawl control member is preferably a friction device that moves the pawl in response to rotation of a rotatable element. The preferred embodiment of the pawl control member is a length of spring wire wrapped around the clutch cover and having a finger extending into a slot in the pawl. The clutch cover rotates with the gear, causing the spring wire to rotate and move the finger within the slot in the pawl. When the finger reaches the end of the slot, the spring wire moves the pawl out of engagement with the ratchet member. When the gear rotates in the unloading direction, the spring wire rotates with the gear due to friction between the spring wire and the clutch cover, permitting the pawl to engage the ratchet member.
REFERENCES:
patent: 950848 (1910-03-01), Gardner
patent: 3301243 (1967-01-01), Lyvers
patent: 3763842 (1973-10-01), Dooley et al.
patent: 4363298 (1982-12-01), Kuhn
Filipak Stanley
Gracyalny Gary J.
Matel Elliot J.
Santi John
Briggs & Stratton Corporation
Dolinar Andrew M.
Michael & Best & Friedrich LLP
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