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US4672929A Expired / Lapsed US ⏱️ 0.0 years remaining

Automatic starting arrangement for an internal combustion engine

Assignee: Andreas Stihl AG and Co KG
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Filing: 1985-12-13
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Granted: 1987-06-16
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Expires: 2005-12-13
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Abstract

Abstract An automatic starting arrangement for a hand-started internal combustion engine is disclosed. Internal combustion engines of this type have a choke flap and a throttle flap positioned one behind the other in the air-intake channel. In order to ensure a reliable starting of the engine independently of manual positioning activities, the invention provides that in the start position the choke flap is coupled with the throttle flap in a position-dependent manner and the choke flap holds the throttle flap in a position between the full-throttle position and the idle position. The choke flap is brought into an at-rest position via an actuating device which is actuable in dependence upon the operating condition of the engine. The choke flap is decoupled from the throttle flap in the at-rest position.

Inventors

  • 👤 Michael Wissmann
  • 👤 Hans Nickel
  • 👤 Jurgen Weber

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-08 20:07
CPC Classifications
F; F02; F02M; F02M1/00; F02M1/08; F02M1/10; F02B; F02B75/00; F02B75/02; F02B2075/022; F02B2075/025

Claims Analysis

Total Claims: 19
Claim 1
Independent Claim 284 words
An automatic starting arrangement for an internal combustion engine such as the manually startable engine of a chain saw equipped with a carburetor defining an intake channel through which air flows to the engine, the engine having a crankcase wherein underpressure develops during the operation thereof, the arrangement comprising: a choke flap movably mounted in the intake channel so as to be movable from a start position to a no-choke at-rest position; first resilient biasing means for resiliently biasing said choke flap into said start position; a throttle flap mounted in the intake channel so as to be movable between a first position corresponding to the idle running condition of the engine and a second position corresponding to the full-throttle running condition of the engine; manually operable throttle lever means connected to said throttle flap for actuating the same; second resilient biasing means for resiliently biasing said throttle flap toward said first position; said flaps being mounted one behind the other when viewed in the direction of air flow to the engine; coupling means for position-dependently coupling said flaps together so as to cause said choke flap to hold said throttle flap against the force of said second resilient biasing means in a predetermined position between said first and second positions thereof when said choke flap is in said start position; actuating means for moving said choke flap into said at-rest position in response to said underpressure; and, said coupling means including decoupling means for decoupling said throttle flap from said choke flap when the latter is in said at-rest position so as to permit said throttle flap to be adjustable by said throttle lever means independently of the position of said choke flap.
Claim 2
Dependent Claim 284 words
An automatic starting arrangement for an internal combustion engine such as the manually startable engine of a chain saw equipped with a carburetor defining an intake channel through which air flows to the engine, the engine having a crankcase wherein underpressure develops during the operation thereof, the arrangement comprising: a choke flap movably mounted in the intake channel so as to be movable from a start position to a no-choke at-rest position; first resilient biasing means for resiliently biasing said choke flap into said start position; a throttle flap mounted in the intake channel so as to be movable between a first position corresponding to the idle running condition of the engine and a second position corresponding to the full-throttle running condition of the engine; manually operable throttle lever means connected to said throttle flap for actuating the same; second resilient biasing means for resiliently biasing said throttle flap toward said first position; said flaps being mounted one behind the other when viewed in the direction of air flow to the engine; coupling means for position-dependently coupling said flaps together so as to cause said choke flap to hold said throttle flap against the force of said second resilient biasing means in a predetermined position between said first and second positions thereof when said choke flap is in said start position; actuating means for moving said choke flap into said at-rest position in response to said underpressure; and, said coupling means including decoupling means for decoupling said throttle flap from said choke flap when the latter is in said at-rest position so as to permit said throttle flap to be adjustable by said throttle lever means independently of the position of said choke flap.
Claim 3
Dependent Claim 34 words
The automatic starting arrangement of claim 1, said coupling means being configured so as to cause said throttle flap to be held in a half-throttle position corresponding to an opening angle of approximately 30°.
Claim 4
Dependent Claim 49 words
The automatic starting arrangement of claim 1, said throttle lever means including a throttle lever operatively connected to said throttle flap, the arrangement comprising detent means for blocking said throttle lever in a predetermined position wherein said throttle flap and said choke flap are held in respective open positions.
Claim 5
Dependent Claim 283 words
An automatic starting arrangement for an internal combustion engine such as the manually startable engine of a chain saw equipped with a carburetor defining an intake channel through which air flows to the engine, the engine having a crankcase wherein underpressure develops during the operation thereof, the arrangement comprising: a choke flap movably mounted in the intake channel so as to be movable from a start position to a no-choke at-rest position; a throttle flap mounted in the intake channel so as to be movable between a first position corresponding to the idle running condition of the engine and a second position corresponding to the full-throttle running condition of the engine; said flaps being mounted one behind the other when viewed in the direction of air flow to the engine; coupling means for position-dependently coupling said flaps together so as to cause said choke flap to hold said throttle flap in a predetermined position between said first and second positions thereof when said choke flap is in said start position; actuating means actuable in dependence upon the operating condition of the engine for moving said choke flap into said at-rest position; said coupling means including decoupling means for decoupling said throttle flap from said choke flap when the latter is in said at-rest position; said choke flap having a shaft pivotally mounted in the intake channel; said throttle flap having a shaft likewise pivotally mounted in the intake channel; and, said coupling means including a choke flap lever and a throttle flap lever fixedly attached to respective ones of said shafts for rotation therewith, said levers being configured to lie one against the other for holding said throttle flap in said predetermined position.
Claim 6
Dependent Claim 283 words
An automatic starting arrangement for an internal combustion engine such as the manually startable engine of a chain saw equipped with a carburetor defining an intake channel through which air flows to the engine, the engine having a crankcase wherein underpressure develops during the operation thereof, the arrangement comprising: a choke flap movably mounted in the intake channel so as to be movable from a start position to a no-choke at-rest position; a throttle flap mounted in the intake channel so as to be movable between a first position corresponding to the idle running condition of the engine and a second position corresponding to the full-throttle running condition of the engine; said flaps being mounted one behind the other when viewed in the direction of air flow to the engine; coupling means for position-dependently coupling said flaps together so as to cause said choke flap to hold said throttle flap in a predetermined position between said first and second positions thereof when said choke flap is in said start position; actuating means actuable in dependence upon the operating condition of the engine for moving said choke flap into said at-rest position; said coupling means including decoupling means for decoupling said throttle flap from said choke flap when the latter is in said at-rest position; said choke flap having a shaft pivotally mounted in the intake channel; said throttle flap having a shaft likewise pivotally mounted in the intake channel; and, said coupling means including a choke flap lever and a throttle flap lever fixedly attached to respective ones of said shafts for rotation therewith, said levers being configured to lie one against the other for holding said throttle flap in said predetermined position.
Claim 7
Dependent Claim 30 words
The automatic starting arrangement of claim 4, said coupling means including a coupling linkage for operatively connecting said flaps to each other in the opening direction of said throttle flap.
Claim 8
Dependent Claim 42 words
The automatic starting arrangement of claim 4, said actuating means including a bellows operatively connected to said choke lever, said bellows also being operatively connected to the crankcase of the engine for responding to an underpressure therein to actuate said choke lever.
Claim 9
Dependent Claim 21 words
The automatic starting arrangement of claim 6, said actuating means comprising a check valve interposed between said bellows and the crankcase.
Claim 10
Dependent Claim 57 words
The automatic starting arrangement of claim 7, said check valve comprising a housing communicating with the crankcase of the engine and having an opening communicating with said bellows, a membrane mounted in said housing so as to be disposed between said opening and the crankcase, said membrane being pretensioned in the opening direction and toward said crankcase.
Claim 11
Dependent Claim 16 words
The automatic starting arrangement of claim 8, said housing being configured to have a storage volume.
Claim 12
Dependent Claim 56 words
The automatic starting arrangement of claim 7, said actuating means comprising a thermostat valve disposed between said check valve and said bellows; and, a conduit interconnecting said check valve, said thermostat valve, said bellows and the crankcase, said thermostat valve being configured so as to change the pass-through cross-section of said conduit in dependence upon temperature.
Claim 13
Dependent Claim 18 words
The automatic starting arrangement of claim 10, said thermostat valve being mounted on a cylinder of the engine.
Claim 14
Dependent Claim 18 words
The automatic starting arrangement of claim 11, said thermostat valve being mounted between cooling ribs of the engine.
Claim 15
Dependent Claim 69 words
The automatic starting arrangement of claim 10, said thermostat valve comprising throttle means for throttling the flow through said conduit, said throttle means having a first cross-section and a second cross-section greater than said first cross-section; and, a bimetal valve having a predetermined switching temperature, said bimetal valve being configured so as to clear said first cross-section beneath said temperature and to clear said second cross-section above said temperature.
Claim 16
Dependent Claim 24 words
The automatic starting arrangement of claim 10, said thermostat valve being configured so as to continuously change a predetermined cross-section in dependence upon temperature.
Claim 17
Dependent Claim 21 words
The automatic starting arrangement of claim 13, said first cross-section being a plurality of throttles of large cross-section connected in series.
Claim 18
Dependent Claim 82 words
The automatic starting arrangement of claim 14, said bellows including: a connecting member connected to said choke lever for actuating the latter, said connecting member being arranged to move through a predetermined stroke distance; and, valve means for controlling the speed at which said connecting member is moved through said distance, said valve means including means for changing the cross-section through which air is drawn from said bellows after said connecting member has moved through a predetermined portion of said stroke distance.
Claim 19
Dependent Claim 60 words
The automatic starting arrangement of claim 16, said bellows including a base; and, said last-mentioned means including a suction opening formed in said base and a valve body operatively connected to said connecting member for closing said suction opening toward the end of the movement through said stroke distance, said last-mentioned means further including a bypass bypassing said suction opening.

References Cited (Backward Citations)

US1957289A Cited
US2030331A Cited
US2158572A Cited
US2762354A Cited
US3237527A Cited
US3831567A Cited
US3907945A Cited
US4123480A Cited
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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) 1990-06-15 1990-12-15 1991-06-16 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1994-06-15 1994-12-15 1995-06-16 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1998-06-15 1998-12-15 1999-06-16 $7700.00 Window Closed / Lapsed

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