US3744468A - Combined rope starter and guard for gasoline engines - Google Patents

Combined rope starter and guard for gasoline engines Download PDF

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Publication number
US3744468A
US3744468A US00257320A US3744468DA US3744468A US 3744468 A US3744468 A US 3744468A US 00257320 A US00257320 A US 00257320A US 3744468D A US3744468D A US 3744468DA US 3744468 A US3744468 A US 3744468A
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US
United States
Prior art keywords
shroud
clutch element
crankshaft
pulley
skirt
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US00257320A
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English (en)
Inventor
D Braun
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Briggs and Stratton Corp
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Briggs and Stratton Corp
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Filing date
Publication date
Application filed by Briggs and Stratton Corp filed Critical Briggs and Stratton Corp
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Publication of US3744468A publication Critical patent/US3744468A/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02N—STARTING OF COMBUSTION ENGINES; STARTING AIDS FOR SUCH ENGINES, NOT OTHERWISE PROVIDED FOR
    • F02N3/00—Other muscle-operated starting apparatus
    • F02N3/02—Other muscle-operated starting apparatus having pull-cords
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B1/00—Engines characterised by fuel-air mixture compression
    • F02B1/02—Engines characterised by fuel-air mixture compression with positive ignition
    • F02B1/04—Engines characterised by fuel-air mixture compression with positive ignition with fuel-air mixture admission into cylinder

Definitions

  • a driven clutch element On an engine having a flywheel blower enclosed in a shroud, a driven clutch element is fixed on the adjacent end portion of the crankshaft, spaced from the shroud.
  • a cooperating driving clutch element is slidable and rotatable on the crankshaft between the driven element and the shroud.
  • a rope pulley is concentrically fixed to the driving'clutch element and has an apertured coaxial skirt projecting towards the shroud and releasably engageable with a clip thereon. Acup-shap'ed outward extension on' the pulley encloses the drivenclutch ele-'- ment.
  • COMBINED ROPE STARTER AND GUARD FOR GASOLINE ENGINES This invention relates to single-cylinder gasoline engines such as are used for powering lawn mowers, air compressors and similar machines; and the invention is more particularly concerned with a simple and inexpensive pull-rope starter for such an engine that also serves as a normally stationary guard for the rotating parts at the flywheel end of the crankshaft.
  • one projecting end of the crankshaft is coupled to a load, and a flywheel mounted on its other end has vanes or blades on its periphery for blowing cooling air across the engine body.
  • the flywheel is enclosed in a sheet metal shroud that distributes and directs the cooling air across the hot parts of the engine.
  • the shroud has a rather large air intake opening concentric with the flywheel, through which the adjacent end portion of the crankshaft projects outwardly, and in most cases the driven element of a starter is secured to this projecting end portion of the crankshaft.
  • the manual starter may be of the spring wind-up type or of the rope-recoil type, but in either case the starting mechanism is usually arranged to have stationary parts which serve as a guard for rotating parts at the flywheel end of the crankshaft.
  • the present invention has as its general object to provide a simple, non-recoil rope starter for small engines that is only slightly more expensive than the one just described, but which has the very important feature of normally serving as a non-rotating guard that protects all rotating parts on the flywheel end of the crankshaft.
  • Another object of this invention' is to provide a simple and inexpensive rope pull starter that is automatically moved to and releasably retained in a position in which it serves as a guard immediately upon starting of the engine and in consequence of such-starting, and
  • FIG. 1- is a view in side elevation of a small engine I 'trating a modified embodiment of the invention and with the device shown in its guard position.
  • the numeral 5 designates generally a single-cylinder gasoline engine that has a blower flywheel 6 mounted on its crankshaft 7, at one side of its crankcase body 8.
  • the flywheel has the usual blower vanes 9 on its periphery for generating a stream of cooling air, and it is enclosed within a sheet metal shroud 10 that partially embraces the engine body and directs the cooling air across the hot parts of the engine.
  • a front end portion of the crankshaft projects beyond the flywheel and out of the shroud.
  • a driven clutch element 14 of the manual starter of this invention is fixed to this projecting end portion of the crankshaft.
  • a cooperating driving clutch element 15 comprises part of a pulley unit 16 that is normally stationary and serves as a guard for the rotating parts at the flywheel end of the crankshaft.
  • the driven clutch element 14 is fixed to the crankshaft 7 in forwardly spaced relation to the shroud 10.
  • the pulley unit is both rotatable and axially slidable on the crankshaft, with its driving clutch element portion 15 normally disposed between the shroud and the driven clutch element.
  • the pulley unit 16 In its normal position the pulley unit 16 is contiguous to the shroud, as illustrated in FIG. 1, and is releasably held against rotation and axial motion by clips 17 on the front wall of the shroud.
  • the pulley unit is manually moved forwardly away from the shroud, out of engagement with the clips and into a position in which its driving. clutch element is engaged with the driven clutch element.
  • the pulley unit can then be rotated for engine starting, by
  • the driven clutch element 14 comprises a generally tubular member having a male helical spline 19 on its cylindrical surface and having a concentric rearwardly opening well or counterbore 20 in which the front end portion of the crankshaft is received with a close fit.
  • the driven clutch element is secured to the crankshaft by means of a bolt 21 that extends through the bore in it and into a concentric threaded forwardly opening well in the crankshaft.
  • the driven clutch element can be keyed to the crankshaft or otherwise confined against rotation relative thereto.
  • a washer 22 that is larger than the outside diameter of the driven clutch element is confined between its front end and the head of the bolt 21 to serve as a stop for the driving clutch element.
  • the pulley unit 16 is here shown as comprising three main parts, namely the driving clutch element which serves as a hub by which the unit rides on the crankshaft, a pulley part 23 in which there is a rope groove 24 and which has an integral cup-shaped forward extension 25, and a skirt part 26 that extends concentrically rearwardly from the pulley part.
  • the pulley part 23 has a rather large bore 27 therethrough that is continuous with the interior of the cup-shaped extension 25. Closely received within this bore is the hub-like driving clutch element 15, which has a female helical spline that is cooperable with the male helical spline 19 on the driven clutch element.
  • the driving clutch element also has as its rear a concentric flange-like enlargement 28 that is partway received in a shallow well or counterbore in the rear of the pulley part.
  • Bolts 29 extending through this flange 28 and threaded into the pulley part secure the driven clutch element to the pulley part.
  • the skirt portion 26 of the pulley unit is made of light foraminous metal, since it must serve as a guard across the air inlet opening 12 in the shroud but must not interfere with flow of air into that opening.
  • the skirt part is more or less bowl-shaped, with a flat central portion, as at 30, having a concentric hole therein in which is received the flange 28 on the driving clutch element.
  • a washer-like ring 33 secured to the pulley part by the bolts 29, overlies the flat central portion of the skirt, around the edge of the hole therein, and the skirt is spot welded or otherwise secured to that ring.
  • the periphery of the skirt terminates in an axially rearwardly projecting concentric rim 32.
  • the rim is shown provided with a bead or edging 33 of rubber like material that extends all the way around it, to enable the skirt to engage the hook-shaped spring clips 17 with a detent action, and to prevent drumming vibration between the skirt and the shroud.
  • the male helical spline 19 extends along only about the front half of the driven clutch element, and the driving clutch element 15 has an axial length which is somewhat less than half of that of the driven clutch element.
  • the pulley unit is in its normal position, in which the skirt 26 is engaged with the clips 17, the unsplined rear portion of the driven clutch element can rotate freely within the driving clutch element.
  • the pulley unit is manually pulled forwardly to disengage it from the clips and to bring the male and female splines into engagement.
  • the engine can then be turned over by means of a rope (not shown) having a knotted end engaged in a slot 34 in the front flange of the pulley and coiled around the pulley.
  • the helical spline connection between the clutch elements causes the pulley unit to be propelled rearwardly. to its normal position.
  • the cup-shaped extension 25 of the pulley portion of the unit 16 projects far enough forward to clear the front end of the crankshaft when the unit is in its normal rearmost position.
  • a concentric hole 35 in the end wall of that extension admits an Allen wrench or other screwdriver to the bolt 21 that secures the driven clutch element to the crankshaft. Because the pulley unit rides on the driven clutch element, removal of the latter from the crankshaft permits access to the flywheel and to other parts that are mounted on and near the projecting front end portion of the crankshaft.
  • FIG. 3 differs from that disclosed in FIGS. 1 and 2 mainly in having its pulley unit 16' formed essentially in one piece, and in having a somewhat different type of oneway clutch.
  • the driven clutch element 14" is a more or less disc-like part that is concentrically secured to the front of the crankshaft 7 by means of a bolt 21 threaded rearwardly into the crankshaft.
  • the driven clutch element On its rear face the driven clutch element has ratchet-like clutch dogs 41 that cooperate with similar dogs 42 on a hub portion 15' of the pulley unit that serves as the driving clutch element.
  • the pulley unit 16' rides directly on the front end portion of the crankshaft, between the driven clutch element and the shroud l0, and its hub portion 15' is a snugly inserted hat-shaped sintered metalbearing that has the dogs42 formed on the front face of its enlarged diameter front end.
  • the bearing of the pulley unit must have low friction and good resistance to wear, inasmuch as the crankshaft rotates inside it, and the sintered metal, imprgenated with oil, provided these qualities.
  • the pulley unit 16 is formed with a circumferential rope groove 24 near its front end, defining a front pulley flange in which there is a slot for the knotted end of a starter rope. From the rope groove rearwardly the pulley unit is formed as a generally cylindrical skirt 26 in which there are numerous axially elongated slots 43 that admit cooling air to the air inlet 12 in the shroud. As here shown, the flywheel 6 is equipped with the conventional rotating screen 44 across the cooling air inlet, but of course that-screen can be omitted.
  • the clips 17' that releasably confine the pulley unit in its normal rearmost position comprise resilient fingers that project forwardly from the front wall of the shroud and have bowed end portions 45 that engage over a circumferential beador ridge 46 on the inner surface of the skirt, at its rear edge.
  • the fingers are under outward flexing bias, and their ridge portions 45 thus tend to engage over the ridge on the skirt with a detent action. Note that when the pulley unit is in its normal position, the fingers or clips 17' are covered by the skirt and cannot catch on clothing and the like.
  • the cup-shaped extension 25' on its front end which encloses the driven clutch element, is preferably formed in two partsQone of them an integral tubular forward extension 48 of the pulley, and the other a cover 49 which fits over the front end portion of that extension.
  • the cover 49 is preferably made of plastic, and its connection with the extension 48 should be a readily removable one such as a snap connection, as here shown, or a bayonet connection.
  • crank-' B a driving one-way clutch element rotatable and axially slidable on the crankshaft between the driven clutch element and the shroud;
  • D. pulley means concentrically fixed to the driving clutch element for axial and rotational motion therewith and around which a'pull rope can be wound;
  • a concentric cup-shaped enclosure means fixed -on the driving clutch element, enclosing the driven clutch element and the portion of the crankshaft outwardly of it;
  • cup-shaped enclosure means comprising:

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)
  • Devices For Conveying Motion By Means Of Endless Flexible Members (AREA)
  • Mechanical Operated Clutches (AREA)
US00257320A 1972-05-26 1972-05-26 Combined rope starter and guard for gasoline engines Expired - Lifetime US3744468A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US25732072A 1972-05-26 1972-05-26

Publications (1)

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US3744468A true US3744468A (en) 1973-07-10

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US00257320A Expired - Lifetime US3744468A (en) 1972-05-26 1972-05-26 Combined rope starter and guard for gasoline engines

Country Status (4)

Country Link
US (1) US3744468A (it)
JP (1) JPS5130213B2 (it)
DE (1) DE2304012A1 (it)
IT (1) IT974965B (it)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4020935A (en) * 1975-07-01 1977-05-03 Facet Enterprises, Inc. Direct cranking starter drive
US4838908A (en) * 1988-07-27 1989-06-13 Kohler Co. Engine air intake screen assembly
US4846115A (en) * 1986-12-25 1989-07-11 Fuji Jukogyo Kabushiki Kaisha Air-cooled engine
US5054537A (en) * 1988-06-03 1991-10-08 Outboard Marine Corporation Lost foam pattern assembly for V-block engine
US5167209A (en) * 1992-03-05 1992-12-01 Dufern Richard L Engine filter assembly
US6022391A (en) * 1999-01-29 2000-02-08 United Air Filter, Inc. Filter assembly for cleaning cooling air for engines
US6162269A (en) * 1999-01-29 2000-12-19 United Air Filter, Inc. Filter assembly for cleaning cooling air for engines
US20020189571A1 (en) * 2001-06-14 2002-12-19 Ryczek Stephen J. Rewind cover guard
US20040089259A1 (en) * 2002-11-07 2004-05-13 Tharman Paul A. Electromagnetic choke system for an internal combustion engine
US20050162026A1 (en) * 2004-01-26 2005-07-28 Mccain Van D. Alternator cover shield
US20100126455A1 (en) * 2008-11-27 2010-05-27 Dolmar Gmbh Starter device

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE202005006678U1 (de) * 2005-04-25 2006-09-07 Dolmar Gmbh Hilfswerkzeuglos montierbares Startergehäuse

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4020935A (en) * 1975-07-01 1977-05-03 Facet Enterprises, Inc. Direct cranking starter drive
US4846115A (en) * 1986-12-25 1989-07-11 Fuji Jukogyo Kabushiki Kaisha Air-cooled engine
US5054537A (en) * 1988-06-03 1991-10-08 Outboard Marine Corporation Lost foam pattern assembly for V-block engine
US4838908A (en) * 1988-07-27 1989-06-13 Kohler Co. Engine air intake screen assembly
US5167209A (en) * 1992-03-05 1992-12-01 Dufern Richard L Engine filter assembly
US6022391A (en) * 1999-01-29 2000-02-08 United Air Filter, Inc. Filter assembly for cleaning cooling air for engines
US6162269A (en) * 1999-01-29 2000-12-19 United Air Filter, Inc. Filter assembly for cleaning cooling air for engines
WO2002103175A1 (en) * 2001-06-14 2002-12-27 Briggs & Stratton Corporation Rewind cover guard
US20020189571A1 (en) * 2001-06-14 2002-12-19 Ryczek Stephen J. Rewind cover guard
US6520141B2 (en) 2001-06-14 2003-02-18 Briggs & Stratton Corporation Rewind cover guard
US20040089259A1 (en) * 2002-11-07 2004-05-13 Tharman Paul A. Electromagnetic choke system for an internal combustion engine
US6830023B2 (en) 2002-11-07 2004-12-14 Briggs & Stratton Corporation Electromagnetic choke system for an internal combustion engine
US20050162026A1 (en) * 2004-01-26 2005-07-28 Mccain Van D. Alternator cover shield
US6998739B2 (en) * 2004-01-26 2006-02-14 Mccain Van D Alternator cover shield
US20100126455A1 (en) * 2008-11-27 2010-05-27 Dolmar Gmbh Starter device
US8534254B2 (en) * 2008-11-27 2013-09-17 Dolmar Gmbh Starter device

Also Published As

Publication number Publication date
IT974965B (it) 1974-07-10
DE2304012A1 (de) 1973-12-20
JPS4926633A (it) 1974-03-09
JPS5130213B2 (it) 1976-08-30

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