US2048783A - Engine starter - Google Patents

Description

July 2s, 1936.

l.. cuRcuRu ENGINE STARTERv Filed June 1o, 193s hw \\\\MM. www

INvgNToR wmv Carrara BY M# ATTORNEY Patented July 28, 1936 ENG STAR i Liborio L. Cure, Ferndale, Mich., assigner of one-half to George E.

Mich.

Gaer, Detroit,

Application .lune 10, 1933, Serial No. 675,308

8 Claims.'

This invention relates to a novel engine starter designed to bring about a soft engagement between the engine and the motor shaft, to then yieldingly operate the engine from the motor and to automatically disconnect the engine from the motor shaft upon normal starting of the engine as well as upon unexpected reverse rotation of said engine.

Starting arrangements now in Wide use utilize the power of the motor to first bring about engagement of a pinion with the teeth of ythe flywheel of the engine and to then turn the flywheel. Attempts have heretofore been made to soften the engagement ofthe pinion and ywheel by interposing springs between the pinion andmeans to bring about the necessary engagement but these only partially cure the difficulty.

Such prior arrangements are also open to objection, due to the liability of breakage of teeth or the springs used to cushion the engagement of the pinion and flywheel and to yieldingly drive said wheel, upon backiiring of the engine.

The primary purpose of this invention is to -overcome the objections heretofore existing by bringing the pinion completely into mesh with the ywheel teeth before utilizing a substantial part of the power of the starting motor to'turn the engine, and by providing a connection beo pinion and ywheel, but in which the arrangement is such that said elements are not brought into firm driving engagement until the pinion has been softly and completely brought into mesh with the ywheel teeth.

45 Still another object of the invention is to improve engine starters of the kind that include a pair ofsleeves in threaded engagement with each other so that automatic disengagement of the pinion carried by one of them occurs upon starting s of the engine, by softening the action of the pinion in engaging the ywheel teeth and by providing for Vthe automatic disconnection of the sleeves from the motor shaft upon reverse rotation of theengine with the pinion in engagement with the ywheel.

. the shaft of standard electric motor such as used Many further objects of the invention will appear as a description thereof proceeds with reference to the accompanying drawing in which:

Figure 1 is a longitudinal section of the assembly of the improved engine starter mounted on for starting purposes.

Figure 2 is a longitudinal section of the arrangement showing the parts in the position they occupy at the time of the turning the crank shaft 10` of an engine.

Figure 3 is an end view of the arrangement.

Figure 4 is a fragmentary longitudinal view of a modification. I

Like characters of reference are used through- 15 out to designate corresponding parts.

Referring to Figure 1, the numeral i indicates a standard electric motor, such as used for starting an internal combustion engine, while 2 indicates the armature shaft thereof. The shaft 2 is reduced in diameter adjacent -the motor providing a shoulder 2a, and is further reduced in diameter adjacent its end providing cylindrical section 2b and a section 2c provided with splines 2d.

A key 3 secures a. cone t of suitable angle t shaft 2. The key-Way in cone 4 permits said cone to be slidable thereon, and sliding movement is resisted by a spring 6b disposed between the shoulder 2a and said cone, and encircling said 30 shaft.

5 is an externally threaded sleeve, freely rotatable and slidable on armature shaft and formed to provide a clutch face 5a. Said face is preferably made of conical form. 35

6 is a drivepinion having teeth to mesh with a part of the engine turning with the crank shaft, such as the flywheel thereof. Said teeth are preferably beveled at the meshing end to prevent abutting with the teeth-of the flywheel. Pinion 6` is provided with a conical bore 6a, and is internally threaded to t'the externally threaded sleeve 5.

Suitably secured'to pinion 6 is a brake drumv i. Said drum i may be made of sheet metal, and pressed upon a. cylindrical portion 6b of said. pinion. The drum is formed to provide a rounded shoulder la.

A clutch facing 8 of suitable material is se- .cured to a' clutch sleeve 9,-said clutch sleeve hav- 50 vpreferably such as oomnioniy used to hold engine valve springs in place and the clutch sleeve 9. The spring retainer may be held on the shaft by a pin I2 or any other suitable means. Spring I0 normally presses clutch sleeve 9 in engagement with the splined part of shaft 2 4and lightly in contact with clutch face 5a on sleeve 5. Clutch faces 5a are formed of suitable material, and may be molded of bakelite or thelike. If desired, securing pins 5c may be formed as an integral part thereof.

A resilient brake arm I3 -of suitable pressure having a helical shape adjacent the end I3a, and a rounded end I3b is secured to motor body I by bolt I4 and lockwasher I5. The end of said arm bears yieldingupon brake drum 1 providing resistance tothe free rotation of drive pinion 6, and the rounded end I3b holds. said pinion 6 away from flywheel teeth when the starter is in its inoperative position. A

In the modification of the invention, illustrated in Figure 4, a motor shaft 2' of uniform diameter beyond the shoulder 2a (Figure 1) is used, and a sleeve I I is keyed thereto, at the end thereof by means of a pin I2'. Said sleeve carries splines that normally engage the splines of clutch sleeve 9' as illustrated. A spring I0 urges the clutch sleeve 9' into contact with the clutch element 5 of the externally threadedsleeve 5 and forces said sleeve into splined engagement with the splined portion of sleeve II .so that in the illustrated position of the parts the clutch sleeve 9' is driven by a shaft 2' on rotation thereof. The vclutch faces may be formed as illustrated in this figure rather than as in Figures l and 2.

Having now indicated the relation of the parts of my invention by reference characters, the operation of the same will be readily understood from the following:

When the electric motor is operated, shaft 2 will rotate clutch sleeve 9 with clutch facing 8 at a relatively high rate of speed. In the position shown in Figure 1, the pressure of spring Ill is light causing said clutch to slip substantially with respect to screw sleeve 5, causing said sleeve 5 to turn slowly and with a yielding or soft drive, this slow turning causing pinion 6 and drum 'l to advance. The pinion will turn much slower than screw sleeve 5 due to the action of brake arm I3 and the engagement of its spiral end I3a with the brake drum. I f resistance is encountered in engaging the teeth of the pinion with the teeth of the flywheel, the clutch will slip until the meshing ends of the pinion teeth properly engage the flywheel teeth when further rotation of the pinion as a unit with sleeve 5 is arrested. 'Ihe pinion is then rapidly brought into engagement with the flywheel teeth but such action is noiseless and smooth due to the fact that the teeth are brought into mesh by the motor operating 'through a friction clutch the elements of which are in light slipping contact. The pinion 6 will advance slowly as it engages the teeth of the flywheel without turning the engine and as the pinion advances, brake drum I slides from beneath brake arm I3. As its movement continues, conical face 6a. of pinion 6 will come in contact with conical face 4a of cone 4, when pinion stops advancing. Inasmuch as spring 4b resiliently resists movement of cone 4, the pinion will be brought to a stop smoothly and si1ent1y. When the pinion stops advancing continued rotation of the shaft causes the sleeve 5 to move toward the right in Figure 2, gradually compressing compression spring ID as shown in Figure 2, thereby automatically increasing the pressure on the clutch elements, thus automatically gradually increasing the torque of motor until the compression and friction of the engine are overcome at which time it will turn the crank shaft and start said engine. When the engine has started on its own power, the pinion is rotated rapidly causing the screw sleeve 5 to retract against shoulder 4d, and the pinion then turned so as to be thrown back against shoulder 5b where the parts are again in their original positions ready for a repetition of the sequence of operation just described.

It will be understood that the cone 4 and engaging conical faces 4a and 6a serve to frictionally couple the pinion 6 to the motor shaft and cause the compression of the spring IIl to provide a firm engagement of the friction clutch elements, only when the pinion is completely in engagement with the flywheel, thus avoiding the use of tooI heavy a spring. The friction clutch elements are intended to hold enough to start the engine but to slip in case of excessive load such as would occur in case of backring.

It will be noted further that cone 4 centralizes the pinion and supports it firmly during the time it is turning the engine. This is of great value in maintaining the pitch centers between pinion i and engine member more accurately, and is more desirable than depending on the screw sleeve alone to accomplish this.

Should the engine backre, the pinion is rotated rapidly in the opposite direction on the armature shaft, causing screw sleeve 5 to slide out toward the end of said armature shaft carrying with it clutch elements 5 and 9 until the splines 9b on said clutch sleeve de-mesh from the splines 2d on armature shaft, allowing screw sleeve 5 and clutch elements 5 and 9 to rotate with the pinion on the smooth portion 2b of the motor shaft, so that said shaft may continue its rotation without any damage whatever to the parts of the starter.

. It will be understood that when'the clutch sleeve 9a disengages the armature shaft splines, it stays out of engagement for the duration of the reverse pressure. When reverse rotation of the engine ceases the spring I0 automatically i returns the sleeve 9a to its normal position at which the splines 9b are in engagement with splines 2d on motor shaft. If the ends of said splines contact to prevent the spring I0 from restoring the parts to their original condition, rotation of the motor shaft will free the splines `from end contact, the splines 2d on shaft 2 being rounded as indicated on the drawings to facilitate the action just described.

What is claimed and desired to be secured by United States Letters Patent is:-

1. An engine starter comprising a motor shaft having a friction clutch element slidably disposed thereon, spline means to connect said shaft and element, means to resiliently urge said element into engagement with said spline means, said last in threaded engagement with each other and slidably disposed on a motor shaft, a friction clutch to connect one of said sleeves to said shaft, engine turning means on the other sleeve, a brake drum on said last named sleeve, a spring arm applying braking pressure on said drum and formed to provide an inclined shoulderand further means non-rotatively secured to said shaft to engage the other of, said sleeves upon predetermined relative movement of said sleeves to cause rmer engagementof said clutch.

3. An engine starter including a pair of sleeves in threaded engagement with each other and disposed for slidable endwise movement on a motoi shaft, a friction clutch to connect one of said sleeves to said shaft, engine turning means on the other sleeve, means to prevent free unitary movement of said sleeves when in disengagement with the engine, and means yieldably engaging said other sleeve to cause rmer engagement of the elements of said friction clutch when said sleeves are in engine starting position.

4. An engine starter including a motor shaft, a pair of sleeves in threaded engagement with each other, one of said sleeves being slidably and rotatively disposed on said shaft and the other having means thereon to engage a part of the engine turning with the crank shaft thereof, a friction clutch coupling said rst named sleeve to said shaft, matching conical surfaces formed on a member non-rotatively mounted on said shaft and said other sleeve to center said last named A sleeve upon said shaft when the means thereon engages said part and to cause rm engagement of the elements of said clutch and resilient means to press said surfaces in contact at such time.

5. An engine starter including a motor shaft, having a splined and an unsplined portion, a pair of sleeves in threaded engagementwith each other and slidably and rotatively mounted on said shaft, and mechanism to cause said sleeves to rotate relative to each other to engage one of them with a part of the engine connected for rotation with the crank shaft thereof, said mechanism including friction 'clutch elements to couple the other of said sleeves to said shaft. one of said clutch elements being carried by said last named sleeve and the other being non-rotatively secured to said shaft, a spring to` hold said elements in 5 engagement with one of them on said splined portion of the shaft and arranged to permit the last named clutch element to shift to said url.-` splined portion of the shaft and thus become disengaged from said shaft upon reverse rotation of said crank shaft.

6. An engine starter comprising a motor shaft, two sleeves in threaded engagement with each other reciprocably and rotatively disposed on said shaft, a friction clutch element formed on one of said sleeves, a cooperating frictionvclutch element on a splined portion of said shaft, a spring to normally urge said clutch elements into light engagement, teeth on the other of said sleeves to engage a part of the engine to start the same, 20 and means to yieldingly contact with the last named sleeve when in engagement with said engine part to cause said first named sleeve and the clutch element carried thereby to move toward its cooperating clutch element and compress said spring to increase the pressure between the clutch elements.

'7. The combination defined in claim 6 in which said shaft is provided with an unsplined part beyond said sleevesv and clutch elements.

8. An engine starter comprising a motor shaft, two sleeves in threaded engagement with each other slidably and rotatively disposed on said shaft, teeth on one of said sleeves to engage a part of the engine to start the same, a pair of friction clutch elements non-rotatively secured to said shaft at opposite ends of said sleeves, springs pressing said clutch elements-toward each other, cooperating clutch elements carried by. both of said sleeves, and mechanism to cause successive engagement of said clutch elements whereby both of said sleeves are frictionally coupled to said shaft.

LIBORIO L. CURCURU.

Images