US2300928A - Engine starter gearing - Google Patents

Description

' Nov. 3, 1942. c. s. JANES 2,300,928

ENGINE STARTER GEARING 4Filed June 2o, 1941 INVENTOR.

Mmm/S: BY is dan/86 www 77 mg:

Patented Nov. 3, 1942 UNITED STATES PATENT OFFICE ENGINE STARTER GEARING Application June 20, 1941, `Serial No. 399,011

(Cl. i4- 7) 9 Claims.

The present invention relates to engine starter gearing and more particularly to a drive of the automatically engaging type adapted to maintain operative connection until the engine is reliably self-operative.

In drives of this type various means have been employed to prevent disengagement of the gearing by the initial explosions of the engine, some depending on the speed of rotation of the drive and some on other factors which differentiate a false start' from a true start.

It is an object of the present invention to provide a novel engine starter drive of the type set forth which is efficient and reliable in operation, simple and compact in construction and adapted for economical manufacture.

It is another object of the invention to provide such a device which-is adapted to connect a starting motor to a member of an engine to be started upon actuation of the starting motor and to maintain such connection as long as the starting motor is energized.

It is another object to provide such adevice which permits the engine to overrun the starting motor quietly and without danger of jamming or dragging.

It is a further object to provide such a device which is dependent on the speed of rotation of the starting motor to keep the gearing engaged.

Further objects and advantages will be apo parent from the following description taken in connection with the accompanying-drawing in which:

Fig. 1 is a side elevation partly in section showing a preferred embodiment of the invention L with the parts in idle position;

Fig. 2 is a similar view showing the parts` in the positions assumed during the cranking operation;

Fig. 3 is a similar view of a slightly mcdiiied form of the invention, showing the parts in positions assumed when the engine starts and overruns the drive while the starting motor is still in operation;

Fig. 4 is a section taken substantially on a line 4-4 of Fig. 1; and

Fig. 5 is a view similar to Fig. 1 showing another embodiment of the invention.

In Fig. 1 of the drawing there is illustrated a power shaft I which may be the extended armature 'shaft of the starting motor not illustrated. A pinion member 2 is slidably journalled on the power shaft forlongitudinal movement into and out of engagement with a gear 3 of an engine to be started. A driving member in the form of a 55y sleeve 4 is fixed on the'power shaft in any suitable manner as by means of a cross pin 5 and has formed thereon or fixed thereto as by welding a radial driving flange E. A driven head I is arranged to surround the pinion 2 and has a radial flange I0 formed thereon and an inter-'- nally threaded sleeve or nut member 8 rigidly iixed therein as by welding or brazing, and in sliding telescopic relation with the adjacent end of the driving sleeve. The threaded sleeve or nut 8 is adapted to cooperate with an externally threaded screw shaft 9 Xed rigidly to the pinion member 2 as indicated at II so as to form a part thereof.

A cylinder I2 of elastically deformable material such as rubber is arranged to surround and closely iit on adjacent cylindrical portions of the driving sleeve 4 and driven head 1, and in loosely abutting relation with the flanges 6 and lil. A barrel member I3 is arranged to surround the flanges 6 and IE), bearing rotatably thereon and loosely surrounding and enclosing the cylinder I 2. Barrel I3 has an inturned flange I4 at one end having a dentate opening i5 adapted to form a splined connection with the toothed por` tion of the pinion member 2, and to abut against the end I6 of the screw shaft S to limit the travel of the pinion member. A thrust ring il is mounted in the open end of the barrel in positiontobear against the rear of the driving flange E, and is conned in the barrel by a split lock ring itl so positioned as to properly limit the depth of mesh of the pinion with the engine gear. The cylinder i2 is so dimensioned that it is not under any initial compression between the anges t and I0 when the parts are in idle position, but it frictionally engages the cylindrical portions of the drive sleeve i and the driven head l. A thimble I9 is preferably provided in the barrel I3 adjacent the iiange i@ to prevent the elastic member i2 from entering the space between the barrel and the flange and thereby becoming abraded.

Means are provided for normally maintaining the pinion in idle position as illustrated in Fig. 1, this means being here` shown in the form of a detent member 2| slidably mounted in the driven head 8 and pressed inwardly so as to bear frictionally on the screw shaft portion 9 of the pinion member 2 by means of a spring ring 22. (Fig. fi.)

Inasmuch as the elastic member I2 is normally loosely mounted between the flanges 6 and I0, the driving connection between the drive sleeve 4 and driven head I is only established by the screw jack action of the threaded members 8 and 9 which compresses the member I2 between flanges 3 and l0. The elastic member |2 therefore cooperates to form an overrunning connection between the driving sleeve 4 and driven head which will permit the pinion to overrun the drive when the engine starts, such overrunning being facilitated by the action of centrifugal force on the elastic member which tends to release it from its fri-ctional engagement with said members. It may, however, in some instances, be desired to provide an overrunning connection between the pinion member and the driven head 1, and this is readily accomplished as illustrated in Fig. 3 by terminating the threads of the nut meinber 8 adjacent the end of the screw shaft 9 when the parts are in idle position so as to permit the screw shaft to run off the ends of said threads. Proper re-engagement of the threads when rotation of the power shaft and its associated parts exceeds that of the pinion is secured by means of a re-entry spring 23 located between the end of the screw shaft 9 and the driving sleeve 4. According to the lpresent invention means are provided for resisting the return of the pinion member 2 to idle position while the power shaft I is being rotated by the starting motor. As here shown this means is in the form of one or more centrifugal weight members such as balls 24 located between the end of the screw shaft 9 and the Adriving sleeve 4, and adapted to cooperate with a flared surface 25 formed in the interior of said sleeve. The surface 25 is so tapered that centrifugal force causes the balls 24 to apply longitudinal pressure to the screw shaft 9 to assist in traversing the pinion into mesh with the engine gear and to resist the demeshing of the pinion as shown in Fig. 3.

The re-entry spring 23 serves to bridge the space between the end of the driving sleeve 4- and the end of the screw Shaft 3 when the pinion is in idle position and prevent the weight members from being lost in shipment or while the drive is dismounted from the power shaft I. In the form of the invention illustrated in Figs. 1 and 2 this function is accomplished by a bushing 26 xed in the driving sleeve and arranged to telescope into the pinion member when the parts are in idle position.

In the embodiment of the invention illustrated in Fig. 5 a power shaft 3| has slidably journalled thereon a pinion member 32 having a hollow screw shaft 33 formed thereon or rigidly fixed thereto as by brazing or welding as indicated at 34. A driving sleeve 35 is xed on the power shaft as by means of a cross pin 35 retained by a split lock ring 31. The driving sleeve 35 has an axially extending cylindrical portion 38 terminating in a radial ange 45 which is slotted for the reception of the outturned end 39 of a drive spring 4| so as to anchor the drive spring to the driving sleeve. The opposite end of the spring 4| is slidably seated in a slot 42 in a nut member 43 which is mounted on the pinion member 32 in position to cooperate with the threads of the hollow screw shaft 33.

Means for limiting the longitudinal movement of the pinion member 32 is provided in the form of a barrel member 44 having an inwardly extending fiange 45 at one end with an opening therein surrounded by teeth 4G conforming to the tooth spaces of the pinion member 32. The teeth 46 of the barrel are arranged to engage the end 4'! of the screw shaft 33 when the pinion member is in operative engagement with a gear 43 of the engine to be started. Longitudinal movement of the barrel member 44 is prevented by a thrust ring 75 I5| which is mounted in the open end of the barrel member in Aposition to engage the rear side of the radial flange 40 of the driving sleeve and is retained in the barrel by a split lock ring 52. The screw jack action of the screw shaft 33 and nut 43 thus causes the spring 4| to be compressed between flange 40 and the nut prior to the application of the cranking torque to the spring. In order to prevent the pinion member from moving out of mesh with the engine gear 49 as long as the power shaft is rotating above a pre-determined speed, one or more balls 53 are mounted in the recess 54 in the cylindrical portion of the driving sleeve 35. This recess has a radially and axially inclined surface 55 so arranged that centrifugal force causes the balls to move axially and assist in the traversal of the pinion member 32 into engagement with the engine gear, and resist return of the pinion member to idle position.

Means for normally maintaining the pinion f'member in idle position is provided in the form of an anti-drift spring 56 located within the screw shaft 33, bearing at one end against a split thrust ring 5l in the interior of the screw shaft and at its other end against a radial ange 53 on a sleeve 59 which is fixed in any suitable manner to the driving sleeve 35 whereby it is anchored to the power shaft 3|. Sleeve 53 serves also to retain the balls I53 when the drive is dismounted. A re-entry spring 6| in the closed end of the barrel is arranged to bear against a shoulder 62 on the nut member 43 so as to insure that the nut member enters the threads of the screw shaft 33 upon rotation of the nut member by the power shaft.

In the operation of this embodiment of the invention 'rotation of the power shaft 3| by the starting motor is transmitted through the driving sleeve 35 and spring 4| to the nut member 43 which thereupon threads itself upon the screw shaft 33, causing the pinion member 32 to be advanced into mesh with the engine gear 49, the meshing movement being limited by engagement of the teeth 46 of the barrel 44 with the stop shoulder 41 at the end of the screw shaft. Further rotation of the power shaft is transmitted to the pinion member causing rotation thereof t0 crank the engine.

When the engine starts, the acceleration of the pinion member 32 causes it to thread itself back out of the nut member 43, but sin-ce at this time the power shaft and driving sleeve 35 are rotating at high speed, the centrifugal balls 53 are moved by centrifugal force out of the recess 54 in the driving sleeve and engage the end of the screw shaft 33 and prevent the pinion member 32 from moving out of mesh with the engine gear 49. The nut member 43 therefore moves to the left, compressing the spring 6| until the nut member runs off the threads of the screw shaft whereby the pinion member is permitted to overrun the drive.

If the engine does not continue to be self-operative, as soon as the pinion slows down below the speed of the power shaft, the nut member will thread itself back on the screw shaft, moving the pinion into full mesh with the engine gear and cranking will be resumed. When the engine becomes reliably self-operative, deenergization of the starting motor by the operatorr causes the power shaft to come to rest,Y whereupon the centrifugal balls 53 permit the pinion member to be returned to idle position by the expansion of thev springs 6| and 55.

Although but two embodiments of the invention have been described and shown in detail, it will be understood that other embodiments are possible and that variations in the design and arrangement of the parts may be employed without departing from the spirit of the invention as defined in the claims appended hereto.

What is claimed is:

1. In an engine starter a power member, an engine driving member, means responsive to acceleration of the power member for moving the engine driving member into engagement with a member of the engine to be started and thereafter rotating the same, said means including an overrunning connection, and means including a centrifugal member responsive to rotation of the power member for assisting in the traversal of the engine driving member into engagement with the engine member and resisting disengagement thereof. n

2. An engine starter as set forth in claim 1 in which the overrunning connection is released by centrifugal force so as to overrun freely.

`3. In an engine starter drive a power shaft, a pinion member slidably journalled thereon, means responsive to acceleration of the power shaft for moving the pinion into engagement with an engine gear, said means including an overrunning connection and means including a weight member bodily movable by centrifugal force to urge the pinion into initial engagement with the engine member and resist disengagement thereof.

4. In an engine starter drive, a power shaft, a pinion member slidably journalled thereon, for movement into engagement with a gear of the engine to be started, said pinion member including a screw shaft, a nut member thereon, a driving sleeve fixed to the power shaft, a yielding driving connection between the driving sleeve and nut member, said driving sleeve having a fiared portion, and means including a weight member in said flared portion movable by centrifugal force to resist disengagement of the pinion from the engine gear.

5. In an engine starter drive a power shaft, a pinion member slidably journalled thereon for movement into engagement with a gear of the engine to be started, said pinion member including a screw shaft, a nut member thereon, a driving sleeve xed to the power shaft, a yielding member connecting said sleeve and nut member for rotation in unison, means including said yielding member for limiting relative longitudinal movement of the screw shaft and nut, said screw shaft being arranged to overrun the nut when the engine starts, and means including a member rotated with the driving sleeve movable by centrifugal force to oppose demeshing movement of the pinion.

6. In an engine starter drive a power shaft, a driving member Xed thereon, a pinion member slidably journalled on the power shaft, means responsive to acceleration of the driving member for moving the-pinion member into engagement with an engine gear, and means including a centrifugal member within the driving member rotatable therewith and movable by centrifugal force to hold the pinionin engagement with the engine member.

7. In an engine starter drive a power shaft, a driving member xed thereon having a longitudinally flared `inner surface, a pinion member slidably journalled on the power shaft for movement into engagement with an engine gear, means responsive to acceleration of the driving member for moving the pinion into engagement with the engine gear, and means within the driving member adapted to be moved outwardly by centrifugal force along the flared interior thereof to assist in the traversal of the pinion member into engagement with the engine gear.

8. In an engine starter drive, a power shaft, a pinion member including a screw shaft slidably journalled thereon, aV nut member on the screw shaft, a driving sleeve fixed on the power shaft', a yielding overrunning clutch connection between the driving sleeve and nut member, and means including a centrifugal member rotatable with'the power shaft for holding the pinion member spaced from the driving sleeve.

9. In an engine starter drive a power shaft, a pinion member including a screw shaft slidably journalled thereon for engagement with an engine gear, a nut member on the screw shaft, said screw shaft being arranged to run out of the threads of the nut and overrun the nut when the engine starts, a driving head on the power shaft, a yielding driving connection between the driving head and nut member, and means including a centrifugal member movable by rotation'of the power shaft for maintaining the engagement of the pinion member withthe engine gear.

CLINTON S. JANES.

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