US3055351A - Starters for small internal combustion engines - Google Patents

Description

Sept. 25, 1962 s. z. SIWEK I 3,055,351

STARTERS FOR SMALL INTERNAL COMBUSTION ENGINES Filed 001.- 10, 1960 4 ts-Sheet 1 28 N INVENTOR.

Sept. 25, 5. Z. SIWEK STARTERS FOR SMALL INTERNAL COMBUSTION ENGINES Filed 001;. 10, 1960 4 Sheets-Sheet 2 INV EN TOR.

51 4/7/6 Z. 5006/? BY Sept. 25, 1962 s. z. SIWEK 3,055,351

STARTERS FOR SMALL INTERNAL COMBUSTION ENGINES Filed Oct. 10, 1960 4 Sheets-Sheet 3 INVENTOR. 5/4/7/4; Z. 50%, BY

I ,if/amgya Sept. 25, I962 s. z. SlWEK 3,055,351

STARTERS FOR SMALL INTERNAL CUMBUSTION ENGINES Filed Oct. 10, 1960 4 SheetsSheet 4 INV EN TOR.

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United States Patent 3,055,351 STTERS FOR SMALL INTERNAL CGMBUSTION ENGINES Stanley Z. Siwelr, Chicago, 111., assignor to Pioneer Gen-E-Motor Corporation, Chicago, Ill. Filed Get. 10, 1960, Ser. No. 61,545 6 Claims. (Cl. 123-479) The present invention is directed to new and useful improvements in starting mechanisms for engines and is particularly applicable to small internal combustion engines of the class commonly found on power lawn mowers.

It has heretofore been proposed to utilize a spring mechanism for starting small internal combustion engines of this class. Prior mechanisms of this type have utilized some form of crank for winding up a spring and then releasing the spring so that the energy of the spring turns over the engine crank shaft for a few revolutions to enable starting of the engine. The major purpose of the present invention is to improve mechanisms of this class by so designing the mechanism that impact forces in the mechanism are held to a minimum with a resultant longer life for the various parts of the mechanism; to so arrange a mechanism of this class that it is easily actuated by remote control; to increase the safety of operation of mechanisms of this class; and to provide a mechanism of this class which is highly rugged in construction and durable in use, and which is, at the same time, economical to manufacture.

Other purposes will appear from time to time in the course of the ensuing specification and claims, when taken with the accompanying drawings, in which:

FIGURE 1 is a side elevation of a typical gasoline engine provided with a starter mechanism of the present invention;

FIGURE 2 is a sectional illustration of the starter mechanism illustrated in FIGURE 1;

FIGURE 3 is a top view of the mechanism illustrated in FIGURE 2;

FIGURE 4 is a side view of a portion of the mechanism illustrated in FIGURE 3;

FIGURE 5 is a sectional view of the mechanism illustrated in FIGURE 4 and taken along the section line 55 of FIGURE 3;

FIGURE 6 is a sectional view of a portion of the mechanism shown in FIGURES 2 and 3 and taken on the section lines 6-6 of FIGURE 2;

FIGURE 7 is a sectional view of another portion of the mechanism and looking in the direction of the arrows of section lines 7-7 of FIGURE 2;

FIGURE 8 is a top view of a modified form of handle and clutch assembly; and

FIGURE 9 is a sectional view of the modified form of clutch illustrated taken along lines 89 of FIGURE 8.

Like elements are designated by like characters throughout the specification and drawings.

With specific reference now to the drawings and in the first instance to FIGURE 1, the numeral 10 generally designates an internal combustion engine of the class to which the present invention is applicable, and as shown in FIGURE 1 is utilized to rotate a cutter blade 11 which is positioned beneath the base 12 of a power lawn mower. Cutter blade 11, as is typical in machines of this class, is coupled to the crank shaft 13 of the engine so as to rotate the cutter blade, through rotation of the crank shaft.

In accordance with the present invention, a starter mechanism generally designated at 14 is mounted on the top of the engine 111 shown in FIGURE 1. As illustrated in the drawing, the starter mechanism 14 includes a handle 15 which is adapted, through mechanism presently to be described, to wind and tension a sprin so that the 3,055,351 Patented Sept. 25, 1962 energy of the spring can subsequently be released to cause rotation of crank shaft 13 and start engine 10.

As is seen best in FIGURES 2 and 3, the starter mechanism includes a housing assembly '16 which is of an inverted cup shape and which is fixed to a shroud 17 for the engine as by means of bolts 18, which bolts are passed through an outwardly extending flange 19 at the base of the housing '16. Housing 16 supports a stub shaft 20 therein as by means of a bearing block 21 fixed to the upper portion of the housing. Handle 15 is fixed to the upper portion of the stub shaft 20 so as to be positioned exteriorally of the housing 16' and to overlie the same as is seen best in FIGURE 2. The handle 15 is sectionally formed, with one section 22 fixed to the stub shaft 20 and the other section 23 hinged to section 22 as by means of a pivot pin 24 The outer end of handle 15, or that end most remote from the stub shaft 20 carries an actuating knob or handle 25 which the operator may easily grasp for rotation of the stub shaft 20. Handle 15 is so mounted that rotation of handle 15 and stub shaft 20 is only permitted in one direction. A coil spring 26 surrounds the cylindrical surface of the bearing block 20 in close fitting relation and has its upper end fixed to handle portion 22 as at 27. The other end of the spring is free to slide on bearing 21. Thus, when handle 15 is rotated in one direction as when the operator intends to crank the mechanism for starting (or clockwise in FIG- URE 2), the spring tends to be unwound, thereby causing a slight radial expansion of the spring and allowing free rotation of the handle with respect to the bearing post 21. On the other hand, when the handle and stub shaft are rotated in the opposite direction, the spring is pulled tightly against the bearing post 21 and frictionally binds against the bearing post, thus preventing this direc tion of relative rotation.

The other end of stub shaft 20 carries a spring support 28 which is rotatable thereon. Support 28 is in the form of an upright cup or drum to which a ratchet wheel 29 is fixed at the lower end thereof. The spring support 28 has a coiled spring 30 positioned therein with one end fixed to the wall of the cup as at 31 in FIGURE 6. The other end of the spring (the inner end thereof) includes an enlarged knob-like portion 3 2, which is adapted for engagement with a recess 33 on a spirally shaped driving member 34, which is fixed to the stub shaft 20 as by means of the pin 26a. Rotation of the driving member 34 in one direction, as for example the clockwise direction in FIGURE 6, will bring the recess 33 against the knob-like portion 32 of the spring and further rotation of the driving member 34 will then wind the spring. The particular spiral shape of the driving member 34 enables the spring 32 to move clockwise with respect to the driving member without abutting against the same.

A pawl support 35 is positioned beneath the spring support 28 and has a generally cup-shaped form. A plurality of pawls 36 are pivoted on the pawl support as by means of pivot pins 37 and are equally spaced about the axis of the stub shaft 20 and ratchet wheel 29. Each of the pawls has a flat end surface 38 which is adapted for abutting contact with similarly formed edges 39 of the ratchet wheel 29. Springs 41 bias each pawl inwardly towards the position illustrated in FIGURE 7 wherein the edges of the pawls are in abutting and driving engagement with the edges 39 of the ratchet wheel 28. The springs 40 have sufficient strength to bias the pawls inwardly when the mechanism is idle and during slow rotation of the crank shaft 13 of the engine. On the other hand, the springs are sufficiently weak that they allow the heavier ends of the pawls (or those with sur faces '38) to move outwardly toward the outer circumferential wall 41 of the cup after ignition of the engine, the centrifugal force then developed being suificient to J swing the pawls outwardly and out of engagement with the edges 39 of the ratchet wheel 29.

The lower central portion of the pawl support is bolted to the end of the engine crank shaft 13 as by means of the bolt 42. The lower portion of the pawl support includes depending finger portions 43 that are stamped from the central portion of the support and are bent downwardly so as to fit into recesses in hub portion 44 of a flywheel 45 that is fixed to the crank shaft 13. The finger portions 43 thus securely key the pawl support to the flywheel and to the crank shaft.

The housing 16 supports a locking mechanism generally designated at 46 in FIGURE 3, which mechanism is adapted to selectively hold the spring support 28 in fixed position relative to the housing 16 and to allow release thereof at the desire of the operator, as is seen best in FIGURES 3, 4, and 5. This locking mechanism includes a lever 47 which is pivoted to the flange of the housing 16 as by means of the rivet 48 which is fixed to flange 19 with a reinforcing plate 49. Reinforcing plate 49 has side portions fixed to the flange 19 and includes an offset end 50 that extends through a slot 50a in the lever 47. Lever 47, as is seen best in FIG- URE 3, includes an end portion which, during pivotal movement of the lever 47 in the direction of the arrows illustrated in FIGURE 3, moves toward and away from the upstanding wall of the spring support 28. A spring 51 is fixed to the outer end of the lever 47 and to the inner end of the reinforcing plate 49. The spring 51 is adapted to hold the lever 47 in one of two opposite positions, either a locked position where its end 47a is positioned counterclockwise from the position illustrated in FIGURE 3 and in contact with the wall of support 28 or a release position wherein the end 47a is positioned clockwise from the position illustrated in FIGURE 3, and where the cutaway portion 47b is opposed to support 28 and spaced therefrom.

As will be noted in FIGURES 3 and 6, the spring support 28 includes a plurality of corner portions 52 which project outwardly from the main body portion of the spring support and which are adapted for abutting contact with the inner end of the lever 47 when the lever 47 is in the locked position. In this locked position, the inner end of the lever will not contact the remaining portions of the spring support, whereas it contacts the projecting portions 52 of the spring support when one or another of these portions is opposed thereto.

A control cable, as is diagrammatically represented at 53 in FIGURE 3, may lead to a remote position so that the operator may move the lever 47 to the release position to allow rotation of the drum 28.

FIGURES 8 and 9 designate another form of clutch between the winding handle and the spring winding shaft of the assembly. In FIGURES 8 and 9 the housing is designated at 60 and carries an actuating shaft 61 which is adapted to wind a coil spring for the subsequent release of energy in the same fashion that the shaft Winds the coil spring in FIGURES 1 through 7, inclusive. The parts of the starter mechanism which are not shown in FIGURES 8 and 9 may be assumed to be identical to those in FIGURES 1 through 7, inclusive.

A foldable handle 62 of the precise type as illustrated in FIGURES 1 through 7, inclusive, is fixed to the shaft 61 and has an outer section 62a pivoted as at 63 to an inner section 62b. The shaft 61 is journalled for rotation in a bearing 64 which is fixed to the upper wall of the housing 60. In FIGURES 8 and 9, the outer surface of the bearing 64 is formed with a plurality of ratchet teeth 65.

A pawl 66 is pivoted to the under surface of the handle section 6211 as at 67 and is adapted for engagement with the teeth 65 of the ratchet. A spring 68 is connected between the pawl 66 and a portion of the handle section 62b, so as to bias pawl 66 into engagement with the ratchet teeth 65.

The ratchet teeth are so formed that they allow rotation of the handle 62 in one direction, as the clockwise direction in FIGURE 8, while preventing rotation of the handle in the opposite direction.

During the winding operation, the spring 68 biases the pawl 66 into engagement with the teeth 65, although during clockwise rotation of handle 62, the pawl simply slides over the teeth. A portion 71 of the pawl protrudes through an opening '72 in handle section 62 when pawl 66 is forced outward by engagement with the high point of the teeth.

After the spring of the starter assembly is wound and ready for the delivery of energy, the outer handle section 62a is folded over the inner handle section 62b, and in so doing the flange of the outer handle section closes opening 72 and prevents outward movement of pawl 66. Thus, folding of the handle brings about a positive lock between the handle and ratchet teeth 65 and prevents any counterclockwise rotation of the handle.

In operation, the operator unfolds the handle 15 to the extended position and moves the tripping mechanism 46 to the locked position. He then cranks handle 15 and during initial rotation of the handle 15, the spring driver 3-4 will move into engagement with the inner end 32 of the spring and will tend to wind the spring 30. This initial rotation will rotate the spring support 28 into a position wherein one of the projecting corners 52 abuts against the inner end 47a of the lever 47. Continued rotation of the handle by the operator winds the spring. During this same initial rotation of the handle, the ratchet wheel 29 which is carried by the spring support 23 also moves through a partial revolution and this partial revolution is sufiicient to cause the pawls to snap into abutting engagement with the teeth of the ratchet wheel 29, as in FIGURE 7. With the pawls thus positioned, the ratchet mechanism is locked in place and ready to deliver rotational energy to the crank shaft 13 without lost motion.

After a few turns of the handle, which is sufiicient to store enough energy in the spring for the starting of the engine, the operator then holds the handle across the stub shaft 20 and into the dotted line position illustrated in FIGURE 2.

Then by moving the lever 47 to the release position, the spring 30 then rotates the spring support 28 and the ratchet wheel 29 carrying with them the pawls and pawl support, flywheel, and crank shaft in a clockwise direction, thus cranking the engine for the starting operation. After the engine starts, the pawls move out of engagement with the ratchet wheel 29, and in the meantime, the spring drum 28 will have coasted to a stop.

It should be noted that if the engine tends to buck or rotate in the direction counter to that direction induced by the spring, the pawls simply move idly over the ratchet teeth, thus preventing any rotation of handle 15.

It should also be noted that the connection between the handle and the stub shaft 15 is such that the handle can only be wound in the direction of winding the spring. Spring forces can never be transmitted to cause counter rotation of the handle by reason of the fact that the spring 26 of the handle binds against the bearing post and precludes such rotation. Furthermore, by the use of spring 26, the operator positively knows the proper direction for winding the handle for the starting operation.

The form of the handle clutch in FIGURES 1 through 7 is extremely quiet in operation. Furthermore, the particular spring clutch described and illustrated provides a substantially instantaneous grip of the bearing surrounding the shaft 20 and insures a positive locking of the handle to the housing.

The particular arrangement of the spring driver and inner end of the spring is advantageous from the standpoint of avoiding impact forces and wear on the spring and driver. In this connection, it should be noted that after the spring has been released to turn over the engine, the inertia of the spring will tend to move the inner end thereof 32 away from the recess 33 and tend to move in a clockwise direction, as in FIGURE 7. The particular shape of the spring driver 34 allows the knob to simply ride thereover freely until the inner end of the spring has come to rest. This is also true in the event that the engine bucks, and causes counterclockwise movement of the spring support 28. In this event the inner end 32 of the spring may simply move around the spring driver without meeting any deleterious impact forces.

Furthermore, when the spring drum 28 and spring 30 are coasting to a stop, by virtue of the expenditure of the springs energy, at which time the end 32 of the spring comes away from recess 33 and moves clockwise around the driver 34, the rising camming surface of the driver then puts a gradually increasing radial pressure on end 32, thus helping the spring and spring support to come to a gradually decelerated and smooth stop.

The positive engagement of the pawl and ratchet, locking of drum 28, and engagement of spring 30 and driver 34, all of which is brought about during initial rotation of handle 15, insures a positive driving connection among the elements without lost motion and deleterious impact forces.

The particular release mechanism is advantageous both from the standpoint of allowing remote control and selective operator control of the starting of the engine and at the same time insuring positive locking of the spring drum 28.

Whereas I have shown and described an operative form of the invention, it should be understood that this showing and description thereof should be taken in an illustrative or diagrammatic sense only. There are many modifications in and to the invention which will fall within the scope and spirit thereof and which will be apparent to those skilled in the art. The scope of the invention should be limited only by the scope of the hereinafter appended claims.

I claim:

1. In a starter mechanism for internal combustion engines, a housing adapted to be mounted on said engine and a drum mounted for rotation in said housing, said drum having a ratchet thereon for cooperable engagement with pawls carried with the shaft of said engine during rotation thereof, a coil spring positioned within said housing and drum and means for winding said spring so that said spring tends to rotate said drum in a predetermined direction, said drum having angularly spaced projections on the peripheral wall thereof, a locking lever carried by said housing and engageable with one of said projections in accordance with the angular disposition of said drum, said projections being spaced so as to allow a predetermined rotation of said drum prior to engagement with said lever, said lever being movably mounted on said housing so as to be selectively moved into engagement with one of said projections and out of engagement therewith such that when moved out of engagement with said one projection, said drum is free to rotate under the action of said spring and cause a consequent rotation of said engine shaft.

2. The structure of claim 1 wherein the outer end of said coil spring is fixed to said drum and the inner end of said spring is abutable against an abutment carried by a winding shaft mounted for rotation in said housing.

3. The structure of claim 2 wherein said winding shaft has a spring driver carrying said abutment, said driver having a camming surface of progressively increasing radial dimension, the camming surface having the greatest radial extension adjacent the abutment surface thereof.

4. The structure of claim 1 wherein said lever is pivoted to said housing and including an actuating cable coupled thereto.

5. A starter mechanism for internal combustion engines including an engine having a drive shaft, a housing mounted on said engine and a drum mounted for rotation in said housing, pawl and ratchet means carried by said drum and said shaft and being engageable with one another upon rotation of said drum in a predetermined direction to cause rotation of said shaft, a coil spring positioned within said housing and drum and means for winding said spring so that said spring tends to rotate said drum in a predetermined direction, said drum having angularly spaced projections on the peripheral wall thereof, a locking lever carried by said housing and engageable with one of said projections in accordance with the angular disposition of said drum, said projections being spaced so as to allow a predetermined rotation of said drum prior to engagement with said lever, said lever being movably mounted on said housing so as to be selectively moved into engagement with one of said projections and out of engagement therewith such that when moved out of engagement with said one projections, said drum is free to rotate under the action of said spring and cause a consequent rotation of said engine shaft.

6. The structure of claim 5 wherein said drum is cup shaped and the upstanding peripheral wall thereof is deformed so as to provide said angularly spaced projections.

References Cited in the file of this patent UNITED STATES PATENTS 2,563,719 Goldberg et a1. Aug. 7, 1951 2,744,586 Blankenburg May 8, 1956 2,804,173 De Millar Aug. 27, 1957 2,869,682 De Millar Jan. 20, 1959 2,950,780 De Millar Aug. 30, 1960 2,955,584 Vakos et a1 Oct. 11, 1960 2,974,658 Russell Mar. 14, 1961 2,997,997 Glenn Aug. 29, 1961 2,999,489 Coughlin Sept. 12, 1961 2,999,490 Hamman Sept. 12, 1961

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