US6848407B2
Expired / Lapsed
US
⏱️ 0.0 years remaining
Decompression device for power generator engine
Assignee: Yamaha Motor Powered Products Co Ltd
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Filing: 2003-03-31
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Granted: 2005-02-01
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Expires: 2023-03-31
Abstract
Abstract A decompression device for an engine reduces pressure in the engine's combustion chamber thereby reducing the amount of force required to start the engine. The decompression device incorporates a decompression lever that cooperates with a cam surface to hold engine valves open longer than normal while the engine is being started. The decompression lever has a weight section and a lifter section. The lifter section is located near a pivot location on the decompression lever and is generally the same thickness as the weight section. The lifter section protrudes beyond the cam gear to hold the engine valves open longer while starting the engine. After the engine has started, the decompression lever rotates into a retracted position to allow the engine valves to open and close normally.
Inventors
- 👤 Misato Kobayashi
- 👤 Satoshi Makino
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 22:34
CPC Classifications
F; F02; F02D; F02D29/00; F02D29/06; F01; F01L; F01L13/00; F01L13/08; F01L13/085; F02B; F02B63/00; F02B63/04; F02D13/00; F02D13/02; F02D13/0276; F02D13/04; F02D15/00; F02D15/04; F01L2201/00; F01L2800/00; F02D2013/0292
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
252 words
A decompression device for an engine having a crankshaft, engine valves, a cam gear disposed between said crankshaft and said engine valves, said cam gear being driven by said crankshaft, and a cam formed on a first side of said cam gear, said cam having a cam surface for opening and closing said engine valves, said decompression device comprising: a decompression lever having a first end portion and a second end portion, said first end portion defining a weight section being urged into an initial position toward the center of rotation of said cam gear, said second end portion defining a pivot opening and a lifter section, said lifter section being located in the vicinity of said pivot opening but being spaced apart therefrom, said lifter section protruding toward said first side of said cam gear through a slot formed in said cam gear, and a pivot pin disposed on a second side of said cam gear, said pivot pin being fitted in said pivot opening to rotatably support said decompression lever, whereby said decompression lever is rotatable by a centrifugal force when said cam gear is rotating, said lifter section being configured to protrude from said cam surface at least when said cam gear is stopped, and when said decompression lever is rotated said lifter section is accommodated within a recess formed in said cam gear, such that said lifter section extends beyond said cam surface or is retracted into said recess depending upon the rotational speed of said decompression lever.
Claim 2
Dependent Claim
252 words
A decompression device for an engine having a crankshaft, engine valves, a cam gear disposed between said crankshaft and said engine valves, said cam gear being driven by said crankshaft, and a cam formed on a first side of said cam gear, said cam having a cam surface for opening and closing said engine valves, said decompression device comprising: a decompression lever having a first end portion and a second end portion, said first end portion defining a weight section being urged into an initial position toward the center of rotation of said cam gear, said second end portion defining a pivot opening and a lifter section, said lifter section being located in the vicinity of said pivot opening but being spaced apart therefrom, said lifter section protruding toward said first side of said cam gear through a slot formed in said cam gear, and a pivot pin disposed on a second side of said cam gear, said pivot pin being fitted in said pivot opening to rotatably support said decompression lever, whereby said decompression lever is rotatable by a centrifugal force when said cam gear is rotating, said lifter section being configured to protrude from said cam surface at least when said cam gear is stopped, and when said decompression lever is rotated said lifter section is accommodated within a recess formed in said cam gear, such that said lifter section extends beyond said cam surface or is retracted into said recess depending upon the rotational speed of said decompression lever.
Claim 3
Dependent Claim
22 words
The decompression device of claim 1 , wherein said lifter section has generally the same thickness as that of said weight section.
Claim 4
Dependent Claim
29 words
The decompression device of claim 1 , wherein said weight section is urged into said initial position by a spring attached to said cam gear and said decompression lever.
Claim 5
Dependent Claim
26 words
The decompression device of claim 1 , further comprising ribs extending from said second side of said cam surface for supporting said decompression lever during rotation.
Claim 6
Independent Claim
124 words
A method of manufacturing a decompression lever for use in a decompression device for an engine comprising the steps of: forming a profile of a decompression lever having a first end portion and a second end portion, said first end portion defining a weight section and said second end portion defining a pivot opening and a lifter section, said weight section and said lifter section being formed of a unitary material having the same general thickness, said lifter section being located in the vicinity of said pivot opening and being formed in the same general plane as said weight section, and bending said lifter section into a position spaced apart from said pivot opening, said lifter section protruding generally normal to said weight section.
Claim 7
Independent Claim
124 words
A method of manufacturing a decompression lever for use in a decompression device for an engine comprising the steps of: forming a profile of a decompression lever having a first end portion and a second end portion, said first end portion defining a weight section and said second end portion defining a pivot opening and a lifter section, said weight section and said lifter section being formed of a unitary material having the same general thickness, said lifter section being located in the vicinity of said pivot opening and being formed in the same general plane as said weight section, and bending said lifter section into a position spaced apart from said pivot opening, said lifter section protruding generally normal to said weight section.
Claim 8
Dependent Claim
43 words
The method of manufacturing a decompression lever of claim 5 , further comprising the step of finishing a surface of said lifter section nearest said pivot opening to provide an arcuate surface on said lifter section that is concentric with said pivot opening.
Claim 9
Dependent Claim
191 words
A decompression device for an engine having a crankshaft, engine valves, a cam gear disposed between said crankshaft and said engine valves, said cam gear being driven by said crankshaft, and a cam formed on a first side of said cam gear, said cam having a cam surface for opening and closing said engine valves, said decompression device comprising: a decompression lever having a first end portion and a second end portion, said first end portion defining a weight section being urged into an initial position toward the center of rotation of said cam gear, said second end portion defining a pivot section and a lifter section, said weight section and said lifter section being formed of a unitary material having the same general thickness, said lifter section being located in the vicinity of said pivot section and being formed in the same general plane as said weight section, said lifter section being bent into a position spaced apart from said pivot section and protruding generally normal to said weight section, and a pivot support formed on said cam gear coupled with said pivot section to rotatably support said decompression lever.
Claim 10
Dependent Claim
191 words
A decompression device for an engine having a crankshaft, engine valves, a cam gear disposed between said crankshaft and said engine valves, said cam gear being driven by said crankshaft, and a cam formed on a first side of said cam gear, said cam having a cam surface for opening and closing said engine valves, said decompression device comprising: a decompression lever having a first end portion and a second end portion, said first end portion defining a weight section being urged into an initial position toward the center of rotation of said cam gear, said second end portion defining a pivot section and a lifter section, said weight section and said lifter section being formed of a unitary material having the same general thickness, said lifter section being located in the vicinity of said pivot section and being formed in the same general plane as said weight section, said lifter section being bent into a position spaced apart from said pivot section and protruding generally normal to said weight section, and a pivot support formed on said cam gear coupled with said pivot section to rotatably support said decompression lever.
Claim 11
Dependent Claim
26 words
The decompression device of claim 7 , wherein said lifter section comprises an arcuate surface facing said pivot section that is concentric about said pivot section.
Claim 12
Dependent Claim
38 words
The decompression device of claim 7 , wherein said lifter section is configured to protrude from said cam surface without a gap when said cam gear is stopped such that said lifter section extends beyond said cam surface.
Claim 13
Dependent Claim
23 words
The decompression device of claim 7 , wherein said cam gear comprises a recess for accommodating said lifter section in a retracted position.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2008-02-01 | 2008-08-02 | 2009-02-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2012-02-01 | 2012-08-02 | 2013-02-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2016-02-01 | 2016-08-02 | 2017-02-01 | $7700.00 | Window Closed / Lapsed |