US2973754A - Starter for internal combustion engine - Google Patents

Description

March 7, 1961 F. 0. DE MXLLAR STARTER FOR INTERNAL COMBUSTION ENGINE 2 Sheets-Sheet 1 o a 2 a Z 4 2 W amw l a I I l r i u w [2 w. a 1 M 8 M a m 9 l I 2 0 lk L a v4 0 d e 1 i F March 7, 1961 F. 0. DE MILLAR 2,973,754

, STARTER FOR INTERNAL COMBUSTION ENGINE Filed 001;. 27, 1958 2 Sheets-Sheet 2 Fio yd 0.12am 21y flaw, ammo/ M fliffaameys Uni edst t s P ten '0 STARTER non INTERNAL COMBUSTION ENGINE Floyd 0. De Millar, Framingham, Mass., assignor to Radian Corporation, Framingharn Center, Mass., a corporation of Massachusetts 7 Filed Oct. 27', 1958, Ser. No. 769,843

4 Claims. (Cl. 123-179) itself with a motor shaft and becomes wound when a v handle member is turned, and which disengages itself after frictional resistance and the resistance ofthe motor compression are exceeded and the spring becomes unwound.

Still another object is to provide a starter mechanism characterized by a high degree of safety in use which will avoid accidental reversing of the handle or other undesirable interference with the operation.

The nature of the invention and its objects will be more fully understood and appreciated from the following description of a preferred embodiment selected for purposes of illustration and shown in the accompanying drawings, in which- Fig. 1 is a fragmentary plan view showing the starter mechanism of the invention mounted upon a motor of the class described above;

Fig. 2 is a cross-section taken on the line 2--2 of Fig. 1; i a

Fig. 3 is a cross-section taken'on the line 3-3 of Fig. 2' and i Fig. 4 is a cross-section taken on the line 44 of Fig.2.

In the structure shown in the accompanying drawings, numeral 2 denotes a motor which drives a shaft 4. In one specific aspect, the invention is concerned with a motor type wherein the shaft is driven about a vertical axis and presents an upper end which can be engaged by mechanism for cranking the motor. The invention is further concerned with a motor which is characterized by a relatively high compression. In such a motor, in addition to ordinary frictional resistance, the relatively high compression tends to impart to the shaft 4 a very considerable resistance to turning forces exerted externally of this shaft.

In accordance with the invention, I have devised, for the class ofmotor indicated, a special spring starter mechanism which is designed to utilize the resistance of the shaft 4 to wind up a coiled spring to a predetermined point. When the frictional resistance and compression resistance of the motor and shaft are exceeded by the energy stored in the coiled spring, a rapid turning of the shaft and motor is realized for starting purposes.

Referring more in detail to the drawings, my improved starter mechanism includes a stationary housing 6 which is adapted to be secured to the top of the motor 2 by fastenings such as the screws 6a which extend through a flanged portion 6b. Mounted for rotation ina bearing portion 8 of the housing 6, isa crank shaft 10 which has secured to its upper end a handle 12. The handle 12 is adapted to be turned in a clockwise direction, as viewed in Fig. 1 and is held at one point, to prevent counterclockwise rotation, by means of a ratchet and pawl unit.

This mechanism includes a ratchet wheel 14 and a pawl 16. The pawl 16 is pivotally mounted within the housing 6 as best shown in Fig. 2 on a pivot element 18, and a spring 20 maintains the pawl in a spring loaded state. The ratchet wheel 14 is secured by rivets 22 to a spring casing 24 which is solidly secured in some convenient manner to the crank shaft 10. Preferably thespring casing may be formed with a shouldered hub portion 24a around which the ratchet is snugly fitted as shown in Fig. 2,,although other arrangements for accomplishing this purpose may be employed.

Located in coiled relationship within the spring casing 24 is a spring 26, the outer convolution of which terminates in a curved extremity 26a (Fig. 3) adapted to be interlocked with a slot 24b in the casing 24. The inner end of the spring 26 is provided with a hook element 28 which is hinged on a spring pivot 30 normally adapted to swing the hook element outwardly when the spring is in an uncoiled position. The book element 28 is designed to provide for connecting the inner end of the coiled spring 26 to the motor shaft 4 so that the springmay be tightened while held by the initial frictional resistance and the compression of the motor.

An important feature of the invention is a novel means for engaging the hook element 28 with the motor shaft 4. This novel means includes a magnet piece 32 which is received in some suitable manner as by means of a recessed bushing 34 keyed to the shaft as shown in Fig. 3. The function of the magnet is to attract and hold the hook element 28 when a winding movement is effected in the coiled spring through the handle 12. A recessed edge of the hook element 28 tends to be drawn around the bushing 34 and becomes anchored in a notch in the bushing closely adjacent to the magnet in the position shown in Fig. 3.

The initial frictional resistance and the compression resistance of the motor hold the shaft 4 in a relatively fixed position for a short period while the spring and casing are wound in a clockwise direction as viewed in Fig. 3. At a point at which initial frictional resistance and the resistance of the motor compression are exceeded by the energy thus stored in the coiled spring, the shaft 4 is turned and rapidly spun While the spring is releasing its stored energy. When the spring has become completely unwound the continued revolution of the notched bushing 34 and the pressure of the spring pivot 30 cause the hook element 28 to move outwardly away from engagement with the magnet and notch described.

From the foregoing description it will be observed that I have disclosed an improved spring mechanism for turning a motor shaft of the vertical axis type and the entire winding operation is adequately protected at all times by means of the ratchet and pawl unit, so that actual release of the handle 12 cannot occur. The entire assembly is of a simplified construction resulting from taking advantage of the compression resistance of certain types of motors. Although the starter mechanism and its operation has been described with respect to a shaft which is turned about a vertical axis, it should be nevertheless understood that gravity forces are not necessary and the operation of the device may also be successfully carried out with respect to shafts which turn about axes other than vertical axes.

While I have shown and described a preferred embodiment of the invention, it is intended the invention may Patented Mar. 7,. 1961 be modified in various respects as defined by the appended claims.

Having thus described my invention, what I claim is:

1. In combination a crank shaft, a motor connected in driving relationship with one end of the crank shaft, said motor having a relatively high compression capable of imparting to the crank shaft an appreciable resistance to turning forces exerted on the opposite end of said crank shaft, a starter mechanism mounted on the motor, said mechanism including a housing, a starter shaft and handle unit rotatively mounted in the housing, a spring casing secured to the starter shaft and rotatable with it, spring engaging means fixed to the crank shaft, a coiled spring having its outer end anchored to the spring casing, means at the inner end of the spring for interlocking said spring with the spring engaging means on said crank shaft, said spring constructed and arranged to wind upon itself when said starter shaft and handle unit are turned, and means for so winding said spring upon itself only in response to resistance in said crank shaft from inertia, initial resistance, and cylinder compression; whereby con tinued turning of said starter shaft and handle unit turns said crank shaft past the point of cylinder compression of said motor and overcomes said initial resistance and inertia; and whereby said spring thereafter releases its said stored energy for urging said crank shaft into higher velocity rotation for starting said motor.

2. A structure according to claim 1 in which the spring engaging means includes a magnet for releasably holding a hook element.

3. A structure according to claim 1 in which said starter shaft and handle unit is prevented from turning in one direction by means of a rachet and a spring loaded pawl, said pawl being mounted for engaging said rachet.

4. A structure according to claim 1 in which the spring engaging means includes a magnet for releasably holding the hook element, and in which the starter shaft and handle unit is prevented from turning in one direction by means of a rachet and a spring loaded pawl, said pawl mounted for engaging said rachet.

References Cited in the file of this patent UNITED STATES PATENTS I l q

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