US3140703A - Cam energized engine starter - Google Patents

Description

July 14, 1964 w. H. BARR 3,140,703

CAM ENERGIZED ENGINE STARTER Filed Oct; 18, 1960 3 Sheets-Sheet 1 IN VEN TOR.

J2 49 A M 47 48 July 14, 1964 w. H. BARR 3,

CAM ENERGIZEJD ENGINE STARTER Filed Oct. 18, 1960 3 Sheets-Sheet 2 INVEN July 14, 1964 w.- H. BARR CAM ENERGIZED ENGINE STARTER 3 Sheets-Sheet 3 Filed Oct. 18, 1960 INVENTOR.

United States Patent 3,140,703 CAM ENERGIZED ENGINE STARTER William H. Barr, 51 Liberty Pole Road, Hingham, Mass. Filed Oct. 18, 1960, Ser. No. 63,449 6 Claims. (Cl. 123-179) This invention relates to a mechanical device for starting small internal combustion engines of the type normally used on power lawnmowers, outboard motors, and the like.

The principal feature of this invention is the ability of the starter to rewind itself as the engine operates without overwinding the starting spring.

In my copending application entitled Automatically Rewinding Engine Starter, Serial No. 58,454, filed September 26, 1960, I have disclosed and claimed a different form of device for accomplishing the same purpose as the present invention, in which I use the reaction of the rotary pulsations of the engine acting on inertia means to rewind the starting spring. The present invention accomplishes the same desired end of providing a starter that will rewind itself as the engine operates, using a lever, actuated by a cam driven by the engine drive shaft to energize the starting spring as the drive shaft rotates. Additional means are provided to prevent the starting spring from being overwound by causing the automatic winding action to cease when the starting spring has been wound to a predetermined tension. Auxiliary features for manually winding the starting spring and tripping the starter to crank the engine are also described.

The object of this invention is to provide a spring type engine starter that will automatically be rewound by the engine to a predetermined tension as the machine opcrates.

Another object is to provide a mechanical device having a spring for starting an internal combustion engine that is automatically rewound by the action of the engine and that may be manually rewound and tripped from a remote location such as the operating handle of a lawnmower or the dashboard of a motor boat.

A further object is to provide an automatically rewinding engine starter that does not require speed reducing mechanisms between the starting spring and the engine drive shaft for proper operation.

Further objects and features of my invention will become apparent from the following description and accompanying drawings, in which FIGURE 1 is a side cross section view of a first form of my invention.

FIGURE 2 is a top cross section view of the first form taken on line 22 of FIGURE 1.

FIGURE 3 is a top cross section view of the first and second form taken on lines 33 of FIGURES 1 and 9.

FIGURE 4 is a partial side view of the automatic rewinding lever and cam taken on line 44 in FIGURE 2.

FIGURE 5 is a top cross section view taken on line 5,65,6 in FIGURE 4 showing the cam and lever in the automatic rewinding condition. 7

FIGURE 6 is a top view similar to FIGURE 5 with the cam and lever in the position they would assume when the starting spring is properly wound.

FIGURE 7 is a partial side view of the tripping mechanism of the first and second forms as indicated by line 7-7 in FIGURE 2.

FIGURE 8 is a top view of the cam, eccentric, stub shaft and cam spring taken along line 8--8 in FIG- URE 4.

FIGURE 9 is a partial side cross section view of a second form of my invention.

FIGURE 10 is a partial top cross section view'of the second form taken along line 1010 in FIGURE 9.

3,140,703 Patented July 14, 1964 FIGURE 11 is a partial side view of the automatic winding lever, cam, and associated elements of the second form.

FIGURE 12 is a partial top view of the second form taken along line 12,1312,13 in FIGURE 11 with the lever in the position it would assume for the automatic rewinding operation.

FIGURE 13 is a partial top view of the second form taken along line 12,1312,13 in FIGURE 11 with the lever in the position it would assume when the starting spring is Wound to a predetermined tension.

Referring now to the first form of my invention in FIG- URES 1 through 8 of the drawings, splined end 1 of stub shaft 2 is coupled to a mating internal spline (not shown) of the engine drive shaft. The stub shaft is rotatably mounted in bearing surfaces in the base plate 8 and bushing 9 which is spot Welded to cover 12 secured to the base plate by screws 13. The base plate is firmly mounted to the engine housing. The stub shaft is held in position axially by thrust washer 11 and the end of the bushing adjacent to the end of collar 18 which is an integral part of the stub shaft.

Clutch drum 3 is rotatably mounted on bushing 9 and is coupled to collar 18 by unidirectional inner spring clutch 4 which is secured to the clutch drum by tang end 6 bent and fitting securely in a hole in the clutch drum hub. The inner spring clutch is wound with an inside diameter slightly smaller than the outside diameter of stub shaft collar 18, being wound in a direction to sieze the collar when the clutch drum rotates clockwise in relation to the stub shaft and freewheel on the stub shaft collar when the stub shaft rotates clockwise in relation to the clutch drum. Cup 5 is pressed on the stub shaft to retain lubricant for the inner spring clutch, with felt seal 7 sealing between the upper end of the cup and the clutch drum hub. Felt seal 10 provides a seal between the stub shaft and the base plate.

The inner end of starting spring 14 is secured to the clutch drum by screw 15 and the outer end looped around pin 16 which is pressed into the base plate.

Pulley 17 is mounted on bushing 9 being free to rotate in relation to the bushing and the clutch drum, within the limits set by stub 21 welded to the cover and ends 24 and 25 of travel limiting segment 32 which is an integral part of the pulley. Rewind cord 27 is wrapped around the pulley as shown and secured to the pulley by looping the end of the rewind cord about pin 28 and clamping the end to the rewind cord by clinched ferrule 26. Recoil spring 20 is wound in the direction to urge the pulley in the clockwise direction, having the inner end secured thereto by screw 22 and the outer end looped about pin 23 which is pressed into the mounting plate.

Upper spring clutch 29 is wound with an inside diameter slightly smaller than the mating diameter of the clutch drum and retained axially between circumferential ridges on the periphery of the clutch drum. The upper spring clutch has loop end 30 secured about pin 28 which is pressed into the pulley and the other end 31 extending tangentially outward from the clutch drum as shown in FIGURES 2 and 7. Lower spring clutch 33 is wound with an inside diameter slightly smaller than the mating diameter of the clutch drum and having loop end 34 secured about pin 36 and the other end 35 extending tangentially outward from theclutch drum. Both upper and lower spring clutches are wound in a direction to sieze the clutch drum when it tends to rotate in a clockwise direction in relation thereto and to freewheel on the clutch drum when it rotates in a counterclockwise relative direction.

Pin 36 is pressed into lever 38 which is pivotally mounted on pin 39 and retained thereon by snap ring 40. Lever return spring 41 is in tension between pin 44 pressed into the mounting plate and the lever to which it is secured by inserting the spring end into a hole in the lever and bending the protruding end to prevent its withdrawal therefrom. The lever is thereby drawn against the circumference of cam 42 which is rotatably mounted in eccentric relation to eccentric collar 43. Pin 46 is pressed into the eccentric collar and stub shaft and has one end extending beyond the circumference of the eccentric collar into a groove in the cam, preventing axial motion of the cam and limiting the cam to approximately 180 degrees rotation in relation to the stub shaft. Spiral cam spring 45 has its ends bent at right angles to the plane of the spring and one end inserted in a hole in the eccentric collar and the other end in a hole in the cam, urging the cam to rotate clockwise in relation to the eccentric collar. Pin 37 pressed into the mounting plate limits the counterclockwise rotation of the lever.

Trip finger 49 is mounted to the cover by clamping the cover between curved retaining strips 51 and 52 by by eyebolt 50 screwed into the trip finger. The trip finger is constrained in a direction parallel to the axis of the stub shaft by the sides of the slot in the cover, and is free to move rotatably about the axis of the stub shaft within the limits of the ends of the cover slot. Trip return spring 48 is mounted in tension between stud 47 welded to the cover and the trip finger. Trip cord 53 is looped through the eyebolt and the loop secured by compression ferrule 54. The trip finger is mounted in position to engage ends 31 and 35 of the upper and lower spring clutches when pulled in a counterclockwise direction.

Considering this first form of my invention in the condition wherein the starting spring is unwound and the engine is not operating, it is necessary to wind the starting spring manually. This is done by alternately pulling and releasing that rewind cord until the starting spring is fully wound. On the pull stroke, the pulley is rotated counterclockwise, rotating the upper spring clutch by the interconnection of pin 28 and driving the clutch drum counterclockwise by the siezing action of the upper spring clutch, thereby winding the starting spring. During the recoil stroke, the recoil spring rotates the pulley and upper spring clutch clockwise, the upper spring clutch freewheeling on the clutch drum which is held against clockwise rotation by the lower spring clutch secured to the base plate through pin 34, lever 38, and pin 39, the lever limited in rotation by pin 37 and cam 42.

When the starting spring has been fully wound, the starter may be tripped to crank the engine by pulling on the starting cord, drawing the trip finger 49 counterclockwise, first engaging the free ends 31 and 35 of the upper and lower spring clutch, and then, with further travel of the trip finger so engaged, driving the free ends 31 and 35 counterclockwise, unwinding these spring clutches and releasing their grasp on the clutch drum. The clutch drum is then free to be rotated clockwise by the wound starting spring 14 and drives the engine shaft in the clockwise direction by the connection of the inner spring clutch 4 with the stub shaft collar, thus cranking the engine in the proper direction for starting.

Once the engine has started and is operating, the inner spring clutch freewheels on the collar of the stub shaft. Cam 42 is rotated to its counterclockise relative position as shown in FIGURE 5 by the friction between its periphery and lever 38. The cam is then in its extreme eccentric position in relation to the stub shaft which is driven clockwise by the engine. The lever will then oscillate about pin 39, driven clockwise by the eccentric cam and returned in the counterclockwise direction by lever return spring 41 when the cam periphery moves away from the lever. This oscillating motion oscillates the lower spring clutch 33 through the interconnection of pin 36, so that the lower spring clutch is alternately rotated clockwise, freewheeling on the clutch drum when the lever is driven by the cam and rotated counterclockwise by the lever spring 41 on the return stroke of the lever, driving the clutch drum with it. The clutch drum is prevented from rotating clockwise by the upper spring clutch anchored to the cover through pin 28, the pulley, segment end 24, and stud 21. This pulsating winding action continues as the engine operates, inching the starting spring to a predetermined tension at which point the tension of the starting spring resisting counterclockwise strokes of the lever, exerts sutficient force on pin 36 to resist the force of the lever return spring, so that the return spring will no longer return the lever into contact with cam 42. When this happens, the cam will be returned clockwise by the cam spring so that the cam is concentric with the stub shaft and out of contact with the lever, thereby stopping the winding action.

When the starting spring has been wound and the engine stopped, the engine may be cranked by pulling on the starting cord as before.

FIGURE 9 is a partial side view of a second form of my invention. The basic differences between this and the first form of my invention already described is in the coupling means between the engine and the starting mechanism, the cam by which the lever is oscillated, and the replacing of the stub shaft with the engine drive shaft. The starting spring, the pulley and associated elements for manually winding the starting spring, upper spring clutch 29, lower spring clutch 33, cover 12, and the tripping mechanism consisting of items 47 through 54 are identical in form and operation to those in the first form of my invention already shown and described.

In. this second form, cam element 57 and circular bushing are securely mounted to engine drive shaft 56 by nut 66. Pins 58 and 59 are pressed into the cam element on which are pivotally mounted pawls 60 and 61, retained thereon by snap rings 62 and 63. Pawl spring 64 has ends bent at right angles to the plane of the spring which fit in appropriate clearance holes in the pawls. The pawl spring is under compression, urging the pawls into engagement with the internal ratchet teeth of clutch drum 73 with a force sufficient to engage the pawls with the ratchet teeth when the engine is not operating but not sufiicient to overcome the opposing centrifugal force acting on the unbalance of the pawls about their pivot pins and urging them out of engagement when the engine operates at normal speeds.

Clutch drum 73 and pulley 17 are rotatably mounted on bushing 67 and supported axially by snap ring 77, with dust cover 68 pressed in the end of the bushing. Lever 70 is pivotally mounted on pin 39 which is pressed into base plate 69 and retained thereon by snap ring 40. Follower wheel is rotatably mounted on pin 76 pressed into the fork end of the lever. Lever spring 71 is in tension with one end secured to pin 72 pressed into the base plate and the other end secured through a hole in protrusion 78 urging the lever to rotate counterclockwise and cause the follower wheel to contact the cam 57. The arrangement for mounting the lever spring results in a toggle action of the spring on the lever, that is, the farther the lever is rotated in a clockwise direction, the less is the counterclockwise force resulting from the lever tension spring. Pin 74 limits the clockwise travel of the lever.

This second form of my invention is manually wound by alternately pulling and releasing the rewind cord, the operation being as described for the first form.

The starter is tripped by pulling on the starting cord as in the first form. The pawls are engaged with the internal ratchet teeth of the clutch drum by the pawl spring so that the starting spring is thereby coupled to and cranks the engine shaft in a clockwise direction. Once the engine starts, the engine drive shaft will rotate in a clockwise direction in relation to the clutch drum and the pawls will override the internal ratchet teeth until the engine reaches a predetermined speed at which the centrifugal force will urge the pawls to rotate about their mounting pins and be completely free of the ratchet teeth.

When the starting spring is unwound as it would be after starting the engine and the engine is operating, lever 70 is caused to oscillate by the rotation of cam element 57 and lever spring 71, winding the starting spring as in the first form. When the starting spring reaches a predetermined tension so that the lever spring cannot overpower it, the lever will not be drawn against the cam and will not oscillate, thereby ceasing the winding operation.

While two forms of my invention have been specifically described and shown, it should be obvious that certain changes could be made without altering the scope and intent of my invention. It is also clear that this should not be restricted to use as a starting device for internal combustion engines, one example of an obvious alternative use being an application in which bursts of energy or high torque outputs are periodically required. My invention would provide such repetitive high energy bursts of power over short periods of time, while requiring only a low power motor to energize the starting spring. Such a motor could be stopped by the position of the lever actuating a disconnect switch when the starting spring is properly wound.

I claim:

1. A releasable device for turning a rotatable body comprising a starting spring, a rotatable cylinder, at fixed base plate, means fixing one end of said starting spring to said rotatable cylinder, means fixing the other end of said starting spring to said base plate, a first unidirectional coupling means, a second unidirectional coupling means, said first and second unidirectional coupling means acting on said rotatable cylinder each comprising a spring tightly wound to sieze said rotatable cylinder when said rotatable cylinder tends to rotate in a first direction relative to either unidirectional coupling means, and releasing means acting on said first and second unidirectional coupling means for releasing their hold on said rotatable cylinder for permitting said rotatable cylinder to rotate in said first direction.

2. A releasable device for turning a rotatable body according to claim 1 with a unidirectional clutch coupling said rotatable cylinder to said rotatable body.

3. A releasable device for turning a rotatable body according to claim 1 with means driven by said rotatable body oscillating said second unidirectional coupling means when "the tension of said starting spring is less than a predetermined value.

4. A releasable device for turning a rotatable body according to claim 1 with manual means for driving said first unidirectional coupling means.

5. A starting device for an engine comprising a rotatable drum, a starting spring having one end attached to the engine housing and the other end attached to said rotatable drum, a lever pivotally mounted to the engine housing, a cam rotated by the engine drive shaft associated with said lever, a first unidirectional coupling means comprised of a spring tightly wound on said rotatable drum unidirectionally coupling said lever to said rotatable drum, manual winding means rotatably mounted to the engine housing, means limiting the angular rotation of said manual winding means, a second unidirectional coupling means unidirectionally coupling said manual winding means to said rotatable drum, a spring acting on said lever urging same in a direction to wind said starting spring, a third unidirectional means unidirectionally coupling said rotatable drum to the engine drive shaft, and means for releasing the coupling between both said first and second unidirectional coupling means and said rotatable drum.

6. A starting device for an engine comprising a rotatable drum, a starting spring having one end attached to said rotatable drum and the other end attached to the engine housing, a lever pivotally mounted to the engine housing, a cam rotated by the engine drive shaft associated with said lever, a first unidirectional coupling means unidirectionally coupling said lever to said rotatable drum, manual winding means rotatably mounted to the engine housing, means limiting the angular rotation of said manual winding means, a second unidirectional coupling means comprised of a spring tightly wound on said rotatable drum unidirectionally coupling said manual winding means to said rotatable drum, a spring acting on said lever urging same in a direction to wind said starting spring a third unidirectional means unidirectionally coupling said rotatable drum to the engine drive shaft, and means for releasing the coupling between both said first and second unidirectional coupling means and said rotatable drum.

References Cited in the file of this patent UNITED STATES PATENTS 2,042,841 Harmon June 2, 1936 2,875,851 Vakos Mar. 3, 1959 2,955,584 Vakos Oct. 11, 1960 2,987,057 Kopp June 6, 1961 3,010,443 Lyvers Nov. 28, 1961 3,032,024 Furlong May 1, 1962 FOREIGN PATENTS 388,025 Great Britain Feb. 14, 1933

Claims (1)

1. A RELEASABLE DEVICE FOR TURNING A ROTATABLE BODY COMPRISING A STARTING SPRING, A ROTATABLE CYLINDER, A FIXED BASE PLATE, MEANS FIXING ONE END OF SAID STARTING SPRING TO SAID ROTATABLE CYLINDER, MEANS FIXING THE OTHER END OF SAID STARTING SPRING TO SAID BASE PLATE, A FIRST UNIDIRECTIONAL COUPLING MEANS, A SECOND UNIDIRECTIONAL COUPLING MEANS, SAID FIRST AND SECOND UNIDIRECTIONAL COUPLING MEANS ACTING ON SAID ROTATABLE CYLINDER EACH COMPRISING A SPRING TIGHTLY WOUND TO SIEZE SAID ROTATABLE CYLINDER WHEN SAID ROTATABLE CYLINDER TENDS TO ROTATE IN A FIRST DIRECTION RELATIVE TO EITHER UNIDIRECTIONAL COUPLING MEANS, AND RELEASING MEANS ACTING ON SAID FIRST AND SECOND UNIDIRECTIONAL COUPLING MEANS FOR RELEASING THEIR HOLD ON SAID ROTATABLE CYLINDER FOR PERMITTING SAID ROTATABLE CYLINDER TO ROTATE IN SAID FIRST DIRECTION.

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